Worried

Lila • I am married with 4 amazing kid's I have twin girl's that are 7 and another little girl that is 5 then I have a little boy that just turned 3 and I have a baby on the way that will be here April 2017:
Beginning to worry I haven't had any pregnancy symptoms this week and have only gained 3 lbs through out the pregnancy but lost 2 this week with all my other pregnancys I gained at least 2 lbs a week I haven't had any bleeding or bad cramps but am worried that something is wrong did any one else have these issues? I am 15 week's 3 days with my 5th