You could be experiencing withdrawal from the meds. Meds need to be stopped gradually and not suddenly. Meds aren't said to be that effective for personality disorders but can help manage some symptoms. Ceasing meds while you are pregnant is also in the best interest of your baby.
Be honest with your partner about how you are feeling. It sounds as though you may be feeling confused and need to feel connected to someone. If you are unable to resolve things with your partner alone make this a subject for discussion in therapy. Pushing him away is a way for you to feel safer, better emotionally. Sometimes we need to do the opposite of what we want.
Talk to your doctor, get good psychotherapy, ask about dbt. These should all be able to help you and your relationship.
How long have you and your partner been together? Remember that pregnancy can enhance mood swings due to the hormones going wild. I don't know what your situation is with your partner, but maybe you guys could go to some couples counseling, as well as you going to counseling for yourself. This is a very important time in both of y'all's lives and it's often hard to get someone back after having pushed them away...