It sounds to me like you may have a uterine fibroid, also known as a leiomyoma. This is a type of benign tumor of the uterus that is made of cells from the outer wall of the uterus. This may be why your doctor
said you have a small wall growing in the middle of the uterus. While the uterine fibroid does not turn into cancer, it can cause pelvic pain, discomfort, trouble with pregnancy and most importantly heavy periods. These periods can be heavy enough that blood loss leads to anemia
. It does not sound like your periods are any more frequent. If your period lasts 2 weeks, but you still have 2 weeks between periods, then you are still having them once per month.
I suggest that you schedule an appointment with your OBGYN. The two of you can go over the treatment options for uterine fibroids, if this is what you have. For starters, your doctor may recommend a non-steroidal anti-inflammatory medication which can help with the cramping. In addition, you will need blood counts done to make sure that you are not anemic. If you are, then you will need to take iron supplements. After you are done having children, you may need a hysterectomy to relieve your symptoms.