I think it's awful you have been given this treatment. I think we can all relate to you with regards to concentration and finding work really difficult. Endo not only affects you physically it affects you mentally. You will have good days and bad days. Have a read of my previous post
I went through a awful struggle mentally last year due to a so called specialist telling me there was no cure and no operation would help. Basically said I needed to manage it medically with the coil. I tried and it failed leaving me with terrible depression, and horrible side affects. I too suffer from migraines, they last 3 days and knock me for 6 but the medics are not interested in this and don't take me seriously.
I cut out loads of things from my diet, cut my hours at work, took up exercise and went to counselling. It's helping but I still have bad days, I still get tired. I've learned not to be so tough on myself, learned that I'm not perfect, learned that I'm not as strong physically and mentally like I used to be. It's difficult but you have to be realistic.
Btw I'm 38, symptoms first appeared in 2009 and I had a lap/diagnosis & laser treatment in 2011. (sorry can you do the maths, I cant get my head round it).
Look after yourself and don't beat yourself up.
Take care x