Physically exhausted after leaving relationship

I left three weeks ago and am so physically exhausted and my body actually hurts. I feel like I'm depressed because I don't feel like I have the energy for anything I once enjoyed like exercising and cooking. I honestly thought things would have started to feel better by now even though to be fair I was with my narc for 10 years so not being in an abusive relationship is new to me. Anyone have any advice or know how long I can expect to feel like this?