don't know i want to keep the baby :(

please don't judge me at all i need a place to vent and i can't take any negative comments right now. im 30 weeks pregnant and in deep depression. the father of my kid broke up with me a little bit before i got pregnant but we were still trying to work things and and still seeing eachother. obviously that's how i got pregnant. he didn't want to keep the baby at first and i never thought i could go through with that and decided to keep her. 2 months after i was still seeing him and having sex with him and i was told he wasn't messing with anybody else. turns out he has been messing with this girl since january. has been sleeping with her, bringing her to his house, showering with her etc. my heart just broke. he had been seeing me less but i still thought we were doing okay. we had been planning to get a house together and he had been telling her the same thing. when i found out i went back to him and he had been promising me he isn't seeing her or talking to her but i can't trust him. he's now moving into a place wth his friends who i honestly don't want around my child because they all smoke weed aren't responsible. i have no where else for my child to go i live with my grandma and was planning on being in a place with him by the time the baby's here. i don't want my baby to grow up like i have. moving from house to house not being able to provide everything for her. i've been thinking about this so much and getting more and more depressed to the point where i don't even want to live. if it wasn't for the baby i would cut off allcommunication with him. all i wanted was a happy family for my baby and a place for her to stay and be happy. nothing is going right and i feel like i'm living in hell. i'm really thinking about adoption but i don't know what to do if anybody could give me some advice :(