The secret to human interests is that they have an arc. A beginning, a middle and an end. Are you still doing the same things you were doing when you were ten? Maybe, but maybe not. I'm certainly not. There were no computers when I grew up. Well maybe a few ;)
It's natural to be bummed out when your interests (work interests, love, play, etc) change. It feels weird and uncomfortable, like we are losing something. It feels bad. You wonder if you are in a deeper funk...like real depression. Will it return? Is it a phase? You don't know.
The best way I have found to deal with this is just to watch. Observe. Hmm. I'm really not feeling this today and haven't for a while. That sucks. Don't get too caught up in it. Let the feelings rise and fall. Keep noticing. What is it that I do get turned on by? Well, I'd really like to be reading right now. So make time and do it. Let your urges take you where they will. Trust them. Let them lead you towards something that does it for you. The author seems to have that covered. He (she) is aware of things that are interesting. Keep doing these things. Let the things that interest you reveal themselves. Have faith in this cycle. It does eventually resolve itself.
I realize that this whole deal is tough due to responsibilities. Family, etc. People are counting on you. You have bills to pay. Appointments to keep. Keep them. Stick to the routine while you explore. This is important, because learning about yourself is easier when the external drama levels are low.
You will know if this course works, because you will feel better. If you still have angst and it is getting worse, then you may need to talk to a real person (a whole other kettle of fish).
My advice: listen and watch. Do what you need to while exploring what makes you happy.