SO confused :/

I feel like my body is playing a cruel joke on me this month. I began having light cramping at 9dpo, and briefly on 10dpo. I began to spot pink/brown on 11dpo, 3days before AF was due. It was very light, and was on/off for the last 3 days. Hasn't gotten heavier, no more cramping. So unlike my normal AF which comes on very strong with heavy bleeding for 3days. I've been so tired, sore boobs for the last week. I took a test this morning (AF due today) and it was negative. I feel like something is wrong with me, I've never had such a short or strange cycle.