Mowly So sorry for your situation again. I think stage 4 so young with a young kid it is a nightmare and its normal to be very depressed, anxious, think why me, grieve for the life you should have had. I have been lucky to have been revised down from it but when they the surgeon told me I was probably stage 4 as a second mass had been found and it could be mets I just collapsed and started crying for my son as he won't cope without me. I also tried to write letters and couldn't though did do a will, also still not signed but at least wishes are known and am trying to train husband and found someone to have the kids if we both die and those things were so difficult and emotional but did give a bit of reassurance.
I found talking to women in a similar situation helped and I am lucky that a few got in touch with me and two of us talk daily. You are welcome to DM me if it helps though I am late 40s so older and also now revised down to stage 2B and will do what I can to help. I am doing chemo at the moment and can feel like rubbish at times, and on steriods I get very waffly and determined and positive but anxious so my messaging on Monday to Wednesday needs to come with a steriod induced warning. I've heard the Facebook group Stage 4 deserves more is very good and maybe worth joining. It is harder being so young as most breast cancer patients are much older than me, its funny to be considered young again at nearly 50 and even at my age I find all the photos of grandchildren on the groups a little difficult at times thinking I may not see mine but I am on a general breast cancer Facebook group so its a mix of stages. I also find sometimes you are better not to do cancer things all the time as it just switches your mind to it, very hard but try and keep it down and have time for other things. Also I spoke to a lady on here a few years back she was stage 4 with bowel cancer and sadly died at 27 or so without having kids but always managed to be OK sounding and I asked her how she wasn't really upset all the time and she said sometimes she was but she realised early on that those emotions were just wasting the little time she had left and she was not going to waste the precious time she had left on them and said they were exhausting as well. I am not sure if I could reach that point as well as her but it was inspirational and did make some sense and I hope it time at least some of the time the hell feelings subside and you can enjoy some time with your family. I would also try counselling and / or meds if you think meds would help. And apologies for my steriod induced rambling.
MissSmiley hope things are improving and you can eat at least some of the time without too awful consequences.
Thanks Top yes my DD is 16 and is capable of booking things, its the money she is after and she spends everything given to her and more. Her brother is the opposite and a mini Papa who hates spending money and even negotiates his school dinners down to 50p a day. A bit embarrassing as we have the money for school dinners fine and as he just eats plain food like plain pasta it looks like he is asking for a discount as we can't afford to feed him but it helps balance DDs spending splurges. She appears to be calming at least, it seems to be triggered on my chemo days, exactly when I don't need it but she is under a lot of stress too and things should improve when her GCSEs are over and my chemo is finished which is mid June. She is normally a lovely girl now and very bright and capable just short bursts of foul moods which are coming in my direction whilst I do chemo, no HRT and steriods, normally I am the most patient and kind person with kids but urgh not at the moment. Though I think she is learning I will answer back when on steriods. 
I hope you get on your travels soon, that is what is keeping me going the thought of an end of the worst bit in 3 months and travelling again.
I am still having pain in the eye socket and watering right eye connected to it. The chemo line think its connected to chemo but do not know exactly what is it but think its OK unless it causes eyesight changes when it would need immediate evaluation as those can be permanent. I also got a numb gums for 2 hours and jaw pain, am wondering if will have any teeth left by the end of this fun. Though my worst fear is losing my sight. But the hospital are at least helping even though they just say what I have is rare and they don't really know about it. My private dentist is amazing so can go to him part way through as well and he has already gave me a full check a month before starting and fine and high fluoride toothpaste and an hours talk on things for free so he is doing all he can. But getting a lot of neuropathy symptoms and bone pain which isn't great for teeth. When my gums went numb it felt like all my teeth were floating and about to fall out at once 
but felt them and they are attached, at least for now. Keep reading tales of 8 teeth falling out after chemo and dental bills well into thousands. That's the issue with these forums but then at least pre warned I went to dentist first and he did all this so was good to know, hospital did not say go to dentist at all but you do need to. Just wish had gone to optician too. Guess I still could but so many medical things are feel bleugh with chemo its the last thing feel like doing.
Love to everyone else. Will stop my steriod rambling here. Sorry.