How is therapy supposed to help

on days like today, I feel like I’m dying my chest muscles hurt I‘m completely fatigue, I keep having episodes of weaknes, I doubt I could muster the energy to stop an intruder if one came through the door, I pushed through work, but I don’t see how I could have made my clients happy now I feel completely worthless to my wife and kid I just don’t get it, the doctor says take this pill and see a therapist but I don’t see how a therapist could help with this, he’ll the doctor can’t even help me!!!! F***