With the absence of any other symptoms, I think it’s safe to wait until your appointment on Monday. Most likely it is something perfectly normal that you wouldn’t notice if you weren’t being hyperaware of what’s going on with your body because you’re pregnant. Every twinge and ache and gurgle suddenly becomes noticeable and it’s difficult to stop wondering what the heck is going on.
Do you have a current copy of What to Expect When You’re Expecting? I’m sure there’s a section that gives guidelines about when to call the doctor if you suspect a problem.
I was a nervous wreck through the first several months of my first pregnancy. I literally counted down the days until I was past the point where the baby had a chance of surviving if she was born premature. She wasn’t. After the ultrasound I was able to relax a bit, but it’s difficult to trust that everything is OK when you can’t see anything!
If you are so worried that you can’t relax, go ahead and call the doctor just for the peace of mind. I guarantee it will not be the silliest/most trivial thing he or she has dealt with in the middle of the night. That’s what the after-hours answering service is for. If the doctor makes you feel like an idiot, you should think about finding a different doctor.