Often times after me and my boyfriend have intercouse I get light spotting or will get what seems like a regular menstral flow (usually bright red) but it only lasts for an hour then fades away within a day. Is this normal?

(Sometimes I get cramps after sex and sometimes they r so bad I don't want to stand up for awhile. It kind of freaks my boyfriend out because he feels he is too rough with me but it happens no matter how careful we try to be.)