Ok A few months ago I worked at a mill turning boards. I worked for 3 weeks. I noticed that my hands started goeing numb and falling a sleep. Mostly at night i would wake up from the pain and when i worked really hard. i took 2 months off to heal. Started weight lifting 3 weeks ago,i havent had any numbness or sleeping of the hands and fingers at all but I noticed that after the first week my weights were going down. I wasnt able to do what i did last week. I do my regular work out but can only do half what i normally do. It feels like my arms are just tired not worked but just tired like ive been benching the bar all day long, not heavy lifting sore.

warm up bar
12 set 135
10 155-65
8 175
5 190
3 200
12 135

I can only do my 12 half of my 10 and none of anything else but my 12 again. could it be because i dont eat all day until after my weight lifting class and eat one big meal a day? or is there something wrong with my arms?