What should I do if I get discouraged easily?

I really want to solve this problem in my life. I’m a really passionate person, and get really excited about many things. But I also get discouraged easily. I wouldn’t call it giving up, but since life has forced me to multitask all the freakin time (see work), I’ve kind of forgotten what it’s like to sit down and work on a painting for 6 hours. I can say that’s I’ve “developed” A.D.D. if that’s even possible. I’m going after things that give me instant satisfaction (see video games)
Could it be a fear of success? should I see a therapist?
Does anyone else feel like this? Did you figure out a solution?
Vacations help, but once they’re over, it’s back to the same old stuff.