Recently bred doe acting strange... Help!

I just go my almost 3 year old French alpine doe bred in the last week, and I was out with her today, and she hunched up and tucked her butt in and kinda turned her head around to touch her side with her mouth, and when she tightened up I heard a release of air and then a small amount of pee hot out and she straightened herself out and was normal again.... Wht is this????