Blood clots and pregnancy

I'm 33 and my husband and I have been together for 9 years (married for 4 ;)).  We are trying to have a baby bit I'm literally scared to death because of my history with blood clots.  The first one I had was when I was 18 and my doctors said it was because I smoked while taking birth control.  The second one was about 5 years ago after a fall and injury to my knee while camping - I put too small of a knee brace on and left it on the whole camping trip.  It was too tight and I developed another blood clot.  I have been fine ever since and doctors told me I did not have to be on blood thinners because I tested negative for all clotting disorders.  However, I've heard that when you're pregnant, you're at a higher risk for developing clots.....I'm terrified.  The last thing I want is to die trying to bring a baby into this world and leaving my husband all alone.