@OhToBeASeahorse, I contacted my GP last year after suffering awful PMT which just got worse after having DS2, I was struggling so much with the lack of sleep plus the responsibility of two on a daily basis I thought I had PND too. The GP was totally understanding. There are options out there and they can really help. I took one option (combined pill ) to even out my hormones but they have given me awful headaches so I have stopped them. I may soon go back to discuss more options I'm just seeing how I get on.
Some days I feel like I'm winning and then others are so hard!
I've come to realise I need to help myself and make sure I feel as good as I can to be able to look after both DS as well as I can, if that makes sense, although most nights I collapse into bed as a burnt out version of my former self. I'm so over the night time get ups.
Definitely speak to your Dr if you think you need to. Sometimes the hardest thing is just making contact. Our GP surgery has an electronic form you can fill in and then they will forward to a Dr.
Perhaps your GP surgery might have one of those, its a bit easier to get it off your chest initially written down.
Do you have a support bubble/childcare bubble? Can someone give you a couple of hours on your own? Sorry if that is TMI about me, just wanted to let you know you are not alone.