Okay so I was 2days late for my period this month and then came on for 3 days which is unusual for me as mine normally last 5-7days. I was fine on the first day of my period but on the second day I had really bad cramps in my belly. And on the 3rd day I was fine. I've been suffering with really bad lower back pain, I've been feeling bloated and have tender and itchy boobs and nipples.. I took a pregnancy test the day after my missed period and got a negative result.. Just need some advice please