My dog went to the vet today, but this afternoon she was acting funny...?

She was tucking her hind in and she was kinda wobbling or limping, and I felt her tummy and it feels kinda tight...is she constipated or did she just hurt herself a little bit?? She was doing a lot more jumping around than normal, plus the vet was feeling around her backside and doing normal vet stuff... If she's constipated, what can I do to make her feel better??