Why is there blood in my pee after sex?

well me and my b/f just stsraed haveing s e x like on the 19th and ever sence then we had s e x like 5 times and when I pee sum timez its got blood in it and before we even stared haveing s e x when I used da bathroom it would burn but I think that was a blater infection but I am scared to ask my mom to take me to the hospital to cause when I pee it bleeds cause it might be from haveing s e x but I dk for shure or it could be something else but I need to know what it is??

That is not normal. You may have an infection or something else. Go see a doctor before whatever is wrong makes you very sick. By the way you are to young but, that's another issue. Take care.