If you get along with your boyfriend's mum, have a chat with her & see if she can help you get to a Dr. I think it's really important to try & get to see one... You seem to have this occur quite frequently, so there is a possibility that you have cysts on your ovaries or some other condition that is making your periods late & erratic. There may be other reasons, but because it happens regularly I think, aside from getting a pregnancy test to rule that out, you need to get a proper check up. Do you have pap smears done regularly? Have you ever had a gynocologist check up before?