Failed sterilization reversal could i be pregnant?

after i had my sterilization reversed in june 2010 i was told by my doc that the op was 100% successful both tubes were open. started trying after 6 months went back had tubes flushed to find out both tubes were now blocked i was gutted. now i am 2 weeks late for period got sore boobs i am tired feeling sick but got negative test results. has anyone ever been told they have blocked tubes only to go on and get pregnant? no nasty answers please