Your handling skills are lacking. This mare doesn't want to be bothered with you, and is showing you she is the boss.
And breeding her did not help anything more than likely. Just gave her more attitude now.
Work on your ground handling skills by finding someone to learn from that knows what they are doing. This mare has no respect for you, and will end up hurting you, and will pass this attitude along to foal more than likely.
Also consider the possibility that something has gone wrong internally, and she needs to be vetted thoroughly. Scar tissue, infection, or what have you.
Horses make me a better person.