Am I worrying too much.

Best Freind stayed over this weekend . Yesterday we were getting ready and I left lo with her while I went to the toilet, I take a while normally, when I came out she was in the spare room with him getting changed and I assume more than just a t shirt because she's never bothered about me seeing her in a bra.when I left her she was doing her makeup. I asked through the door do you want me to take him. But she said nah we're fine. For context my mum has made me very nervous about abuse because she was abused and so I don't trust people. My mind is racing that something could have happened and it's my fault. My friend is a lovely person who I couldn't imagine doing anything. but I'm raised to think people are secretly up to no good.