Feeling bad after masturbating

I recently started masturbating again, and overall my mental and physical health has improved because of it. However after climaxing I notice I just feel really shitty. Not even mentally guilty, but just physically really awful. My muscles feel sore and I feel really weak after. It pretty much immediately diminishes that good feeling. I am in recovery for two EDs and therefore my bodys pretty malnourished (however I've been doing pretty good eating wise recently) so I'm not sure what this extreme fatigue and pain is about. Do any of you experience this or have recommendations?