Twinges in lower abdomen?

I asked a question earlier and was going to include this but forgot. From the beginning of my pregnant, and i mean before i even took a postive test, i had twinges in my lower abdomen. My dr tol dme it is just my uterus stretching and nothing to be wroried about unless it is accompanied by cramping and bleeding, or if it gets painful. I had these twinges up until last week, my 13th week. I am now 14 weeks as of today and i feel no twinges, i havent fo ra few days. I am a bit of a worry wart as i have miscarried before. I know tha tmor ethan likely if i miscarried i would know, but could something be wrong that id ont feel them? or is it just one of those things that wont be constant everyday? I know taht at some point symptoms subside a bit and come back off and on, i still worry!