I began spotting on September 19th to the 21st. It would start and then stop and was very light. Which is unusual for me. I began to have nausea, breast pain, and fatigue, which made me believe I may be pregnant but the test was negative. Then the same thing occured again on October 8th and 9th. Yesterday, October 26th, I suddenly started getting extreme pains in my lower abdomen and uterus as well as bleeding very heavily. I'm wondering what would cause this.