Avoiding pregnancy but not by choice

My youngest baby is 5 months old and hubby and I would love to have more children. We currently have 3. When I had my last c-section in october, my ob/gyn told us that we absolutely shouldn't have any more babies due to my uterus being so thin. My husband watched the procedure, and both him and the doctor said my uterus looked like an over filled water balloon and that they could see the baby's hair swishing around through my uterine wall.

My question is.. is there any possible way I could strengthen my uterus? Could I possibly carry another child? Is there hope? Or should we just give up and get a tubal.