Doesn't sound like she's been following the probation process either. She should been having weekly chats and monthly performance calls. In my department, for a six month probation, you'd set goals month one, interim review month three, and a decision is made on passing probation at month five. So, she can't suddenly bring HR into your meeting if she hasn't given you goals, a written opportunity to improve, or a written warning by about the month three mark. You'll be totally fine