I Have Been Gaining Weight I Weigh 95 Pds And

I have been gaining weight I weigh 95 pds and went to the doctor weigh 103 then a month later gain to 109.9 pds and my stomic has been getting bigger I had the marena in me for five years had it took out in march of last year, and I my boyfriend and I have been trying to have a baby and every time I take it says no and I have periods and they are light, they last 2 to 3 days, I just started to get puke just today, kinda wondering if the marina can give me faluse negative on pregnancy test, and be pregnant.