I want to know what I'm supposed to do when I wrote a question, nobody gives me the answer I'm looking for, I find the answer I'm looking for and post it. Accepting my own answer (if possible) sounds illogical. Can I close the question? Should I delete the question?
You can answer your own question, and then after two days you can accept your own answer.
If the question was worth asking in the first place, then somebody may very well ask it again.
Why not save the world the effort and just leave the question and answer visible to everyone?
Information wants to be free!
In this case the accepted practise is to leave it a few days before posting your own answer then leave it for a few days more before accepting it.
There's nothing intrinsically wrong with doing this and leaving the question and accepted answer on the system will help anyone else with the same problem.
By leaving it a few days between each step you're giving others the chance to post a better answer.