Start Over
If U fell off with a training regiment, U need to start over. Starting over means starting from the bottom. Do not jump straight back into lifting the weight that U used. Go back to the beginning of the program. Eat the humble pie.
That U fell off at all means U couldn't keep the pace U'd kept before. U can call that unsustainable. What makes U think U can jump back into an unsustainable workload? U create a sustainable workload by starting over and ramping back up, to find the sustainable place.
U've injured yourself trying to jump back in. Injuries impede progress far more than slower training. Start over from the beginning.
U can progress faster than U did the first time, but U must start at the beginning. U can reach the frontier of your practice in less time, but U must start over. Trying to jump back in just does violence to your body.
Starting over means starting which means starting small.