sleeping pills and alcohol are both CNS depressants. In individual who is habituated to both, when he decreases or stops either or both, fits (jerks) are a possibility. In ur case, if the no jerks have occured in past, as such, it is likely sleeping pill related. Doing EEG will help differentiate both the condition. if pill related, u need to slowly taper and stop it following a structured regimen. But, more importantly, i feel u r going through some stress for which u have chronic sleep problem, alcohol consumption and u experience i feel my heart muscles and body muscles getting weak. All these should be treated holistically by neither sleeping pills, nor by liquor, rather by separate class of psychotropics and of course, psychotherapy.