Overtraining is actually a prolonged state of “under-recovery” where your body does not have the ability to properly repair itself. It takes weeks or even months to recover from this state; your capabilities are heavily depressed, often even below starting level. This state can only be reached through chronic overworking, so you will hopefully never reach it—the only way to get to this state is by not getting enough rest for several consecutive months. Deload properly and you will have nothing to be concerned about.