i had the same probaly dude. on my old blade the crank had come loose and i ignored it then it worn. this happened a cuple of tiime because im a noob . once you get new cranks ( if you do ) id give them a tighten every time you ride your bike and tighten the pedals aswell, i do it. may be a lil but anoying but its worth it .. 
 
hope this helps 
 
matt