I am not sure if this is the right community to post this on, but here I go.

Quite recently Alevels results have been published and my newsfeed is flooded with screenshots of steller results.
Almost all of them have As or A*s which is amazing to see hard work pay off.
Now if any one has sat for alevels you'll know how terrifyingly difficult the subjects are. And re takes are VERY common.

So here is the problem, I am 25 years old, nearly done with uni.
But one of my biggest ptsd trigger remains Alvls results. I did not pass ANY subject. I won't say I am not intelligent but during that time I feel Like I was burnt out, the classes I went to I knew no one and had no friends or anchor and I didn't even feel motivated, everytime I tried going through the material I was petrified of failure, I used to completely freeze up. Some days I wouldn't even get out of bed, to cope w the stress I masturbated a lot. 
None of my friends know this. I feel so ashamed and I find myself incredibly dumb.

I got into a uni that accepts GED. And no one I know has set for a GED.

My mother taunts me about it till this day. I still feel like a failure.

So here I am years later, wondering if could ve done a better job and what it would do to my self esteem.
How do I cope w this?