Well, some women exercise their entire pregnancies including
running. (jogging type of
running). Maybe you did overexert yourself though (which trust me, if I broke into a sprint right now, I'd have aches and pains as it would shock my muscles and ligaments as they have NOT been running lately. :>)).
I had a lot of pressure in my vagina when in my third trimester. That is normal.
See how you feel and maybe it was just a bit much for you.