Low Sex Drive HELP

So I’m 21 years old. I had a baby 8 months ago & currently on birth control (if any of this info matters) but I have a low sex drive. I enjoy sex with my boyfriend a lot but idk I can’t get into like I used to or I don’t get horny as easily anymore. I know it bothers him because he thinks there might be someone else because of this but I assure him that’s not the case. I tried to tell him my sex drive sucks now and idk why. It’s not like I don’t wanna have sex but I just don’t want it much anymore. I hate it because I just want my sex drive good again. Has any other woman had this problem? Or what did you do to help it?? Pls no judging just need pointers