always worring about my chemo

Is this normal? I worry its going to quit working. Anyone know the longest a person has been on cisplatin and gemzar? I wonder if the reaction i had to the cisplatin might be a sign my body has had enough?
I try not to talk bad about my chemo, because it is saving my life! And i feel blessed that it is working. I do wonder if anyone knows what treatment md anderson puts cc people on after the gemzar and cisplatin quit working. Are there any signs we can look for when it comes to chemo and when it stops working?
Sorry for any typos im on my phone.