Not sure where else to post this so here I am.
Background information: My friend recruited me to come work with her. Everything was fine, with some narcissistic behaviors and red flags that I swept under the rug, for about 10 months.
About two months ago, I hit my limit and tried to have a conversation with her about her increasingly irratic behavior and how it was affecting the department. It didn't go well. I hadn't been able to get through everything I wanted to say before she dared me to resign. So I did. I take things very literally so I thought she actually wanted me to leave.
I submitted my letter of resignation and the next day, her boss comes to me to offer me a department transfer if I don't leave. He said nice things about my performance and that he was desperate to keep me with the company.
I thought about it for a couple of days and accepted a transfer to another department. I was in the new department for three weeks when that department lead resigned. I was offered the department lead position. After consideration, I accepted.
Yesterday, at work, I was told by a colleague in my old department that my former friend/boss was trying to tell another manager that I'm not a good fit for the position and it should be offered to someone else.
She has also gossiped and lied about me to other people at our company and is trying to gain sympathy and turn them against me.
I have only recently realized that this woman is terrible person who will stop at nothing to sabotage me now that I'm not her ignorant minion anymore. I am not good at handling situations like this. What should I do going forward?