so you were drawing after a dry fire to see if it was ok? if those cables are under full tension like bow is locked up it could go boom, press if you have one if not I have seen and heard of ppl putting a rachet strap around the limbs to take pressure off cables and then take it in to shop to press it and get it checked out.
I had a new bow that the draw stop were not set right and bow locked up at full draw, string went limp cables got super tight and just as i set bow down it went boom shooting limbs thru wall, string wrapped around my wrist leaving snake like marks and black and blue lucky i think just to get away with that. was not pretty.
but you will need a press no matter what to get string back on, and if you dry fired it and then string came off at 3/4 draw most likely have a bent cam, axel, weak limb something is wrong.