Cycles

I am on my 3rd cycle of IVF. My fertility doctor says that after this 3rd cycle I will get pregnant for sure. I am afraid that after the completion of 3rd cycle in case I don’t get pregnant, what will I do? I am just too much afraid. Can I have one more try for IVF from the start? Is it really possible? Any one in the same boat. I am Sorry for rambling with my stress but I don't know what to do next. I am trying to be positive and relax. Please help. TIA.