anyone gone through this ?

Is this normal to happen ?? I am 5"3 before having my almost 2 year old son I was 132 and always had regular periods, when I had him I was 173 and my periods got irregular and I also gained a lot of weight and having hard time loosing it I am now 180 something. Last October I got on birth control for 3 months to just help me regulate my period after third month I just stopped it. My last period was Dec 11 until 17 and I still haven't gotten my period all my tests are negative. This is the longest that I haven't had my period ...