I'm 17 + 2 in first pregnancy and have started to get really bad pain in my tailbone. I have a desk job and sitting down today was agony! Actually, getting up from sitting down wasn't much fun either ... not so much waddling as hobbling 
Is it normal to be having pain this early? The baby's still only tiny!
Does anyone have any tips on the right way to sit at a desk / cushions etc I could use to be a bit more comfortable? Would exercises help?