Hi, I'm a 19 year old female who for awhile have been having a problem with my peeing. It usually starts after I have intercourse with my boyfriend, I tend to need to go to the bathroom more and my bladder will fell up a lot quicker, for a example, this evening I peed once and then about 10 mintues later I would have to go pee again with a full bladder even though eariler I thought I had emptied it. My mother told me it's probably a water infection or something wrong with my back (I have back problems because of a snowboarding injury when I was a kid) but I'm worried it's something a whole lot worse like cancer or something where I won't be able to have kids. It usually lasts for about 3 or 4 weeks but then it goes away depending on how much I have sex in those weeks. I also have a feeling of something pressing on the inside of my stomach but it's almost like a muscle twitch, that as only started a day ago. Right now I'm on my period but this peeing a lot as been going on for about a month; it likes to disappear and when I think it's gone, it comes back only worse. I need help, I already went to the doctor awhile ago the last time I was like this and after taking a sample of my pee and waiting for about a hour, he told me I didn't have a water infection, so I'm not sure what's going on with me. Also, my bowel habits have changed within the last 3 months and I find I can't drink a lot of milk now. I just want someone to tell me it's not cancer so I can't stop worrying about it so much and get on with my life.. I'm so scared.