Curious as to what could cause this ?

Ok I have unprotected sex a lot with my boyfriend! 21st jan I come on my period 28th jan I came off my period my periods norm hurt a lot this one never I didn't even notice it.. 31st jan I came on a really heavy at first and lasted 6 days ''period'?' what was it? Why did I have two periods the second has made me feel nauseas and the cramps were bugging me? What could cause this?? i thought i was pregant at first before i came on 21st because of alot of symptoms and then that happened and now i feel like i did before my period again my breast ache!! and feel full and i keep getting an ash smell up my nose?? what could of happened???? anyone???