I want to leave my boyfriend.

Long story short, me and my boyfriend have only been dating a couple months. I just got out of a three year relationship, which the current boyfriend knows about, we really weren't looking for anything serious. I was going to end it until I took a pregnancy test and it came out positive. I wasn't being careless either, we used protection. Now he says he loves me and is planning our whole future together. He's been staying at my house non stop and is smothering me. I told him repeatedly I like my alone time, but he said he doesn't trust me alone. I feel trapped. I tried breaking up with him but he cried and I didn't know what to do, so I said I need him to leave for a few days so I can think. He still stops by when I ask him not to and blows up my phone. I was on anti depressants and obviously stopped when I found out I was pregnant, so I'm trying to keep sane and put my mental health and my baby first. I understand stopping my meds and the hormones may be a factor as to why he's driving me crazy, but I can't handle it right now. I want to talk to him tonight and tell him how I feel , and explain to him it's not like I'm going out looking for someone else. I think it's important for me to have some alone time and figure out who I am while I can, like I said I just got out of a three year relationship. I can't do that with him breathing down my neck. I'm honestly not happy with him. And I feel terrible because I want to be with the father of my child but I never expected this, and I don't want to force myself with someone I don't want to be with. I don't want to end it 100%, I'll explain to him he can still come to the appointments and we can still go to dinner , I'm not cutting him out of my life. I'm not trying to give him mixed signals either , if he wants to find someone else is be okay with that. Basically I feel guilty for not wanting to be with the father of my child. Any advice would really be appreciated because I don't know what to do at all.