Im freaking out!!!

So first of all, Im 21, and I started masturbating at age 13-14, on average 4-5 times a weak, but when I hit 18 I cut it down to once or twice a week, and have been going like this since then,

lately (last 2 months to be specific) I have been over doing it (once a day or twice) due to some stresses. during these 2 months I had no problem but after that when I cut it down again, I found my erections to be softer than usual and not nearly as hard as it used to be just a a few months ago, but what REALLY freaked me out is the duration, normally it would stay erect even after masturbating, now it lasts just a few seconds, If im watching porn and look a way for a few secs - boom no more erection, even the orgasms are a fraction of what they used to be...

I am terrified that this is erectile dysfunction, having that when im only 21... also I now tend to get shaky hands and legs under any stress, it used to be only right after masturbation but now for much longer. (been 2 weeks now with the shaky hands...) ,

Im worried that if im with a girl I wont be able to "preform" any more...I know what you are thinking its probably because of these "stresses" but no it cant be anxiety or stress becuase this happens in masturbation and ive been masturbating for years... so its either over masturbating or something worse....

I might be blamed because I have a very lazy life style, dont do much physical activity... I have no idea what to do....

if any one went through this tell me your experience and if you solved it