Trying To get pregnant.... legs cramps, still feel to vomit

hi i'm confused had my breast swollen for about a week before my peroid which was due the 16th Feb and nothing happen on the 17th was feeling to vomit which i did and on the 18th in the evening started flowing really light up to sunday 19th miday later that evening i had a heavy flow that fill 2 pads and next morning went light again. usually when my peroid is due i have leg cramping and when it arrives it goes away but today is the 21st and i still have legs cramps, still feel to vomit and little pains in my stomach. took a pregnancy test last night and it was negtive.