Need advice about boyfriend

So my boyfriend talks about a girl at work all the time. I never really gave it much thought till now. They always text each other not work related stuff. He’ll show me memes she sent him or jokes. I never asked my boyfriend about her. I’m starting to get very suspicious about him talking to her. Should I ask my boyfriend about her? I’m 12 weeks pregnant so idk if it’s my hormones causing me to start thinking something is going on between him and that girl. Idk. Please telling me if I’m overrating