You strength is down because your body stop producing testosterone because you've messed up your cycle and started a second cycle right after pct. It has nothing to do with how long you've been training. That would have no bearing on your strength going down. It may have been from lack of sleep or not eating enough but most likely it is from you screwing up your body with one cycle after the other and not enough recovery time. Also sometimes people have bad days in the gym, its a fact of life. There is no need to over-analyze it. Good days and bad days. I'd suggest getting on a good PCT and taking 1-2 weeks off from the gym.
