Big belly

My belly is huge for being only 5 weeks. Is anyone else showing?  I was like 121 lbs and am 5'7". Granted, I wasn't in the beat shape right before I got pregnant, but I was still only a size 4!  Anyone else showing yet?  This is my first pregnancy, so sorry I'm creaking out about everything. My appt isn't until the 6th to see the nurse midwife.