Endometrial Biopsy

Has anyone in here had an endometrial biopsy done before? What does it entail? Does it hurt? How long does it take? Are u given anesthesia? I was ordered to get one in August and chickened out. My last 4 cycles have been horrible coupled with cramps that incapacitate me for the first 3 days of my 7 day cycle. So today (I started my cycle yesterday) I finally called the hospital to make the biopsy appointment and to ask for something stronger than Ibuprofen 800 (it only takes the edge off and wears off after about 2hrs). I was scheduled to get the biopsy done Dec. 5th at 10:30a. However, I'm in hella pain and have nothing to take. The pain is bad. I don't think I can hold out until next Tuesday. The only way I can describe it is that it feels like the first contractions u get in early labor. So, I think I'm just going to go into the ER tomorrow where I'll probably end up getting the biopsy done. I'm just scared as hell!