My pony seems unhappy what do I do?

Maybe the vet should check her out. I'm not saying you aren't taking good care of her, but sometimes horses have problems that we can't physically see. I don't think it's right that she is acting up now that it's spring. I'm not sure how she acts when you ride her or during turn out, but make sure she doesn't act abnormal during turn out. Hope you find what's wrong!