Hello - wow, you sound upbeat! Glad to hear you are feeling better than yesterday:) I read yesterdays and really felt for you. Having a baby, being P is scary enough without having to deal with some of the stuff you do. How is your relationship with your mum? Is she local? If you feel you can, I would tell her - she will prob rant and rave for a bit, but unless she's a beast, she will come around - it's not as if you are 14 for gods sake! She could be good support for you???? And it may be that you don't' have to give birth alone.
Talk to your councillor, hope they are good support for you? Use every resource you can, ask midwife for classes/groups/workshops - get in the spirit of things:) It will keep you busy, bring you into contact with other local mums and support groups. Try to focus on the positive and not the negative, and dont' waste your time googling negative stuff! There are a million horror stories out there, and I would say the majority are vastly exaggerated.
It will be scary, and hard being a single mum if that's how things end up, but women have done it before and will do it again. I can remember my Gran telling me how she lost her husband a month before the war ended, whilst she was 8 months pregnant - she went on to lead a very happy life with more children, and was also in her early 20's. It's a tough job, but I reckon you can do it (easy for others to say I know).
P.s. IFFFF you and your other half go your separate ways, make sure you get custody of the dog! I have a terrier (airdale) and he has been more supportive and sweet than the other half at times:) Love him! He will get you out the house for walks and be good company:)
Keep your chin up - it's easy for others to give good advice when not in the same boat, just be the best you can for yourself and your baby x