I think my best friend dated my ex when they both knew I liked her
Is the best friend he or she?
A she which I do not mind, but problem is that she is a bitch, I hate her
Friends like that are not very respectful of you. I hope you dumped them both at the time. Toxic people like them just mess with your head for years and years when in contact.
Yes I dumped them both. This bitch is always telling people she is so nice but she is not and a liar
That is a great first step.   Make sure that you meet other people who treat you better so that you can more easily move on from them.