The cramps I had with my first 3 periods after getting my IUD were about 1/4-1/2 as bad as contractions. Heat on my back, tylenol+ibuprofen+a mild muscle relaxer (midol or pamprin, can't remember which...but I remember having to read the back so that I didn't double up on either the tylenol or ibuprofen -again, can't remember which had what in it 7 years later-) helped tremendously.
When my appendix was about to rupture though, it was EXACTLY as painful as giving birth. If you still have your appendix, try pushing in on your lower right side of your belly (far in, and essentially parallel to your belly button but over to the right) and then taking your hands away really FAST. If you nearly black out and see stars (it's called rebound pain)...have someone drive you to the ER.
Otherwise it's tylenol+ibuprofen+moist heat. You could also put a call into your doc for a mild relaxer, or pick on up OTC. Raspberry leaf tea (great for labor because it helps concentrate the contractions) works for some people, but makes it worse for others.
Good luck! Gawd, I HATE cramps.