What happens on breaking an independent contractor agreement?

I am a medical assistant working as an independent contractor. I turned in my resignation notice on 2/10 with 3/11 as my last day since the contract requires a 90 day notice but a little later said that the Nevada State law governs over the agreement. I spoke with the employer and let her know if there was a job opportunity, I hope she’d understand and would work around my new schedule but she seemed to brush it off. I received an excellent opportunity to start on the 10th but my employer wants to speak to my new employer to see about keeping me for the next two months and working around my current schedule to be able to train a new person whenever one is picked but working normally until then. I have tried to get my current employer to agree to let me train when is convenient for me and my new schedule but they are not willing to comply. Am I bound to my old employer?