It isn’t actual weakness because sometimes I will feel it at the gym and be bench pressing 200+ pounds at the same time. 

It seems to be more of a perceived weakness. It started around the time I developed a fear of fainting or feeling sick/out of it. It also doesn’t have a specific trigger that I can identify as sometimes it happens for no reason. Sometimes is accompanied by nausea or feeling faint.

Does anyone have any experience with this as it has been causing extreme anxiety for me as of late.