I so embrassed and feel bad about this?

Well I'm pretty sure your brother wont get mad about this because he know all girls have to go through this so he's not really going to be blaming you. I would be really embarrassed to but things like this are going to happen to some people o and maybe get the next pad size to hold in more blood. I hope I helped but just don't be embarrassed it's ok it will be fine... If you still think hes mad at you then just talk to him about it. Good luck girl!