Dont know how it happend Ruptured again can anyone help ?

I ruptured my Achilles Dec19th 2007 had opp three days later Dr said the opp went well, went into cast for 6 (six) weeks. had one replaster to move my foot a little bit (not much) then off to rehab 45mins over 2 weeks, rehab nurse said i was ok to go back to work (self emp Carpenter) the weekend befor going back to work i was doing my exercise’s, when i felt a nasty pull again went straight to hospital (A&E) they said i had just pulled a muscle and use the R I C E method, two weeks later my Dr told me i had ruptured my Achilles again but in a different place, i have now had my Achilles re-built and am at 5 weeks after opp.