AITA for getting blood all over my boyfriend’s sheets?

I was having a really bad cramp that day, and didnt have a wearable pad so used the middle sized ones with the wings. Probably shouldn’t have though bcs it made a really big red spot on his sheets.

I eventually has to tell him. He didnt seem angry just a “meh” face

But after a few days he constantly made fun of it with his friends and made nicknames like “bed wetter” or some stupid nicknames to shame me. My friends support me saying that hes an asshole but kids are giving me weird looks now.

When I confronted him about it he told me that I should have told him about my periods in the first place and now im starting to think hes right. AITA?

Also sorry if this sounds really terribly written. Its rly late at night writing this