Dear Samantha ~ Sweetie, you had a very bad experience, and I understand the trust issue. But you have to remember that not everyone is like that. Unfortunately you and your sister had bad experiences with your bosses, but that doesn't happen often. How you two got bad bosses is just a coincidence.
Normally, bosses are half-way decent, and quite good to their employees. So try not to worry about any prospective boss. I'm sure he/she will be just fine.
It seems to me that you are quite depressed. Have you talked with your doctor about this? Perhaps you need a referral to a good therapist --- I think you need someone to talk to. Therapy would be a good idea, as depression can be quite serious. I've suffered from it since I was a child, and have been on medication for almost 40 years so I can spot depression in others quite easily and you DO seem depressed! Talk with your doctor and see if you can get a referral to a therapist, ok?
God bless and please take care. Hugs, Lee