I am genuinely so confused

Last night I was extremely exhausted, so as I was texting with my boyfriend I told him I might go to bed soon. He agreed it was a good idea, so I went to bed around 9pm, which is very early for me. I was on my heaviest day of my period last night so I had to wake up every two hours to change everything out since it was so heavy. This morning I text my boyfriend a good morning text, and everything is fine until he asks what time I fell asleep. I thought that was weird because I told what time I was going to bed last night. When I reiterated I went to bed at 9pm his mood changed and he started interrogating me, telling me that he thought I was lying and he “wanted the truth”. At this point I am beyond confused because I was telling him the truth. He demanded “the truth” from me one more time and that is when I added I had to wake up in the night a lot because I was on my period. I asked him what was wrong because I was so confused and that is when he told me I shouldn’t worry about it because it was a misunderstanding, but he still sounded upset. I’m just confused because it sounds like when I would get on my phone while I was in the bathroom, he somehow knew and thought I was just lying to him? But there is no way he would know I was on my phone which is why I don’t know how he knew I wasn’t asleep the whole night.