Running Withdrawal??

This might sound insane but this is my first marathon and I injured my groin right as I was starting my 3 week taper so I couldn’t run much at all leading into this weekend. Few jogs here and there and I mostly cross trained on bike while my groin healed. I’ve felt so exhausted like my body has been hit by a bus and been to multiple doctors who said I’m not sick so curious if bc I somewhat had to cold turkey my running coming off my peak mile week to heal, it is now effecting my body? If anyone has experienced this before please let me know because I cannot figure it out and not sure what else I can do to feel better and shake this exhaustion before Sunday.