Are they wet burps (e.g. a little vomit mixed in...gross I know)? If so, that could be a sign of acid reflux. I have it and I have it really bad. It's also accompanied by a feeling that something is stuck in my chest/throat. Tums don't work for me so I take Zantac 150 2x a day. It helps out immensely but does not cure the burps 100%. I feel for you. I find it almost as bad as the nausea I experienced for 21 weeks straight.
yikes. i thought this whole nausea thing is only in the first trimester, the 2nd trimester you're back to your normal self until 3rd trimester. i guess it comes to show you that every pregnancy is different. hope you feel better now.