the baby is probably just getting ready to come down
As BTS said it could be the beginning of labor or it could be braxton hicks contractions. Dont' rely on the mucus plug. I've given labor 5 times and only had bloody show/lost my plug with one as well. If at any time you are uncertain, call your doctor or go to L & D. Don't feel silly if they send you home saying it's nothing, it's better than having an emergency delivery at home or on the way to the hospital becuase you didnt know you were in labor.. It's happened.
You can tell if it's a contraction...when you feel the pain, rub your hand around your entire uterus. If it's REALLY hard around the ENTIRE thing it's a contraction. If it's not hard at all or just in spots most likely it's due to the baby moving aruond and pushing on your cervix.
Amy, First off congrats on your little bundle of joy!
Second off, just because you haven't lost your mucous plug does NOT mean you can't be in labor. In fact most women lose their plug while pushing their baby out. I have had 5 babies...and only lost my mucous plug/bloody show with one of them.
Your cramps, and pain that is coming and going could in fact be the starting of labor. Make sure you time them, and get to the hospital as soon as they are very painful (can't talk or walk through them) and regular. First time pregnancies can take hours and sometimes even days of labor until you get to hold your little one. I labored 72 hours with my first!!!!
Just keep an eye on your pains. Drink lots of water, and try laying on your left side for 15 minutes, and then switch positions. If the pain is still there after drinking a few glasses of water and switching positions, it is most likely that your in the beginning stages of labor.
Don't rely on your mucous plug....pay attention to your body, your over all feeling. Good luck, and hopefully you will be holding your precious baby soon!