Could it be fibroids?

I'm 21 years old and am on the birth control Seasonale (the one where you only get 4 periods a year). I've been taking it for about 2 years, and although have occassionally had breakthrough spotting, the past few months have been really bad. Not only do I almost always constantly have a thick brownish discharge, but every few weeks I get a period that lasts a couple of days with very heavy bleeding and horrible cramps.
I called my doctor and she told me to wait until my annual - that it's probably related to my BC pills. But I find it odd that I've been taking them for so long and am just now having these problems.
I know I'm young, but my mom had really bad fibroids (the size of a grapefruit) and had a hysterectomy a year ago because of it.
Was wondering if anyone out there has an opinion on this, or something else that may be causing it?

There's probably LESS to worry about instead of more. Your thick brown discharge is probably due to a combination of the normal shedding of the lining of the uterus (the endometrium) with some old (1-5 days old) blood. The cramping happens when your uterus tries to expel the ol;d stuff (your period). While fibroids are very common, they mainly opccur in women older than you. I don't believe you have a problem now with any fibroids. Of course, fibroids are benign areas of smooth muscle - the same as makes up the walls oif the uterus. What you may need now for peace of mind is to have an internal pelvic exam by your Gyn doctor to get some reassure you. Is another type of contraceptive a possibility that would reduce your heavy cramping, or can your doctor prescribe something to relieve your cramping? Ask the doctor.