So today I go to the gym today after 2 days of rest to do shoulders, I warm up, do rear delts everything is fine. I move on to DB press and.. holy shit everything feels heavy. Weight that I usually do for 10-12 reps I cant even do one. I even checked the weights to make sure I didn't grab 10 or 20 lbs heavier than I wanted. I finish the work out and every other exercise felt pretty normal. I'm really confused by this. My form was fine, nutrition is good as I've been eating more/higher quaility foods, I got 8-9 hours of sleep the past few nights and hadn't done shoulders or chest for like 6 days... we'll see what happens next week I guess. I'm just wondering if this has ever happen to anyone else?