I have a tb mare that has been going great the last few months but on the last ride reared twice and threw me both times. After the first rear I checked her feet and comfort of the saddle and both were fine. She was acting up a bit before hand with a bit of head throwing but to rear to the point I thought she was going to go all the way over was out of the blue. She rode another 25 minutes before she threw me again. Any advice on why she may have done this and more importantly how to stop it. She was eager to head for home and holding her back was frustrating her.