Feel like ending my life 😞 need advice

So I am currently 37 weeks pregnant me and my bf/baby’s dad are together and have been since the day I got pregnant which we planned together I am 20 and he’s 28 we live together and are expecting a baby girl I am so excited and I love my daughter dearly since becoming pregnant I stopped taking my antidepressants but since then things have been going down hill in my life they all stem from my bf and just before I got pregnant we had split up and he moved out he ended up sleeping with another woman in the 2 weeks we where apart and she got pregnant I got pregnant the day we got back together and that’s when I was told by the girl she was pregnant with my bfs baby 😢 I sometimes wish I would of got up and left him that second but I love him and I thought we could make things work as our little family which was going fine but unfortunately the other girl gave birth yesterday and things have been extremely hard for me he firstly didn’t tell me that he was going to visit the baby but made up another excuse instead he then left and travelled 2 hours away to where she lives and has been there ever since I then seen on fb that she had uploaded a photo of the baby and my heart broke 😞 I would never wish any harm on a child but at that second I wished he would just disappear so I then text my bf and he confirmed he was seeing the child and that he didn’t want to upset me he says he loves me I know he loves our daughter we live together and spend every night together we go out on dates and we go to the scans together and talk about our daughter all day everyday and now all of a sudden he’s with another woman and a newborn baby and it’s breaking my heart it feels like he leaving me and going to stay with his new family 😞 I feel so down and can’t stop hysterically crying I’d never hurt my child but if I wasn’t pregnant I don’t think I’d still be alive 😞 what do I do