I feel like an awful idiot.

I took a class to get my first hive back April and started keeping bees in May from a nuc. I tried to feed them, and wax over the plastic frames, but they never built new wax past a frame. They never ate much. Now it's totally infested with SHB, and I just feel like a fucking idiot that I did that too them. I don't know if there were never strong to begin with or had to many varroa mites from the start or all the things I did wrong. I just feel awful. Sorry just wanted to let someone know because I'm pretty ashamed I messed up so bad so quick.