Post gynecologist visit... ???

Well OH did a sperm sample a few months back and it came back 'satisfactory' the nurse today now decided that must of been a mistake and that it is now 'extremely low' and we will need IVF to conceive ??? I am gutted. Also as well I need to lose at least 4 stone before that can happen as I am overweight. Feel devastated ? has anyone been told anything similar?? Please help xxx