Oh no, I am so sorry your therapist resigned. It's hard to find one that' s a good fit I think and that's such a shame you have to start over. Could that therapist maybe recommend someone? Maybe you could call your insurance and then look up the therapists online and then check out their reviews and/or speak with them on the phone first to make sure they are worth trying out? Maybe you could find one that does DBT if you are interested in pursuing that. Teletherapy could maybe be an option to look into if you're in an area with very limited options (I don't know much about it, though).
I would say that if you were having a good experience with the last therapist it's a positive sign therapy could work for you, just a matter of finding the right one. Your mental health is worth it, you are worth it!