Someone put my mind at ease please

So a little after quarantine started my best friend messaged me showing my bf (of about 8 months) on a dating app. She didn’t match with him or anything just saw him and sent it to me but this was not the first time she had done it. She showed me it a little after we started dating because she thought it was a little weird that he was on there and with me but i was like ok he probably had it before he met me so no big deal and dismissed it and told her to keep an eye out for me if she notices anything else. She sent me a pic again in like the middle of the relationship because she noticed that his profile pic had changed and so had his bio. I was a little suspicious but I never came out and said anything to him. The final time she sent me a picture was what I’m talking about now which is a couple weeks ago when quarantine was just starting like late March and she sent another pic because a picture was added to his profile and again his bio was changed. This time I did speak up because I was like what the heck that makes no sense. So I asked him about it through text because of the lockdown (we don’t live together) and he said that he hasn’t used it, showed me a screenshot of girls who added him on snap and said it makes no sense for me to accuse him when he wasn’t adding them back. At this point I didn’t know what to think because my best friend was saying oh that’s just too suspicious it’s weird but my bf was saying that he hadn’t used it and so it took a lot in me but I decided to trust him. I love him so much and he is a good bf. Other than this he has given me no reason to believe that he has bad intentions with me and he has always seemed like the loyal kind of guy. So I said I’ll trust him and if he said he wasn’t on it, he wasn’t on it right. But I can’t stop thinking about it. Like I really want to believe him but I just get weird feelings like it kinda doesn’t make sense. The day I brought it up to him he immediately took his profile down and I had my friend check for me and she said his profile hasn’t been on it since (she has to check cause i don’t have dating apps). But I’m such an over thinker and I can’t stop thinking maybe he was using it and texting other girls throughout our relationship? I know for sure it was most likely never physical if he was on it but I just don’t know how to get rid of these thoughts. We’ve been good since then and still haven’t seen eachother because of the lockdown but every now and then I’ll remember it and start feeling sick, like physically sick and ill start feeling this hate towards him (which idk where that comes from). My two biggest fears in a relationship are dishonesty and cheating and I just hate having the feeling that maybe I was being played and I let it go.... what do you guys think?? Am I just overthinking it and dragging it out too long?? How can I stop?? Sorry for the long post but I’ve been keeping this in for this long and really wanted to let it out, any advice would be great thank you 💞

Btw we’re both nineteen if that means anything