I wouldn't let loose sweats take me to the doc. Maybe if I lost radical amounts of inches or lots of confirmed pounds. But if you are eating well and were not before getting pregs, it might be that your body is tossing off a bit of extra weight, and that would be a good thing not a bad one. Ask at your next appointment when they weigh you on the medical scale.
Its normal I had them with my first and now with my second .
By the second trimester you lose a lot of the bloating and is just baby. Don't worry you're good