Don't self diagnose, it's bad.
When you're not an addict, you will search about signs of gambling addict and there are few signs that same like your habit, you will diagnose if you're an addict and vice versa. It's better for someone visit a doctor and ask them if you're an addict or not, so you will get a proper answer since they more know about your problem.
while I do agree with you on the fact that it is not a good idea to self diagnose, since one is always biased for oneself, I think that visiting a doctor is unnecessary. Addictions are easy to spot, especially from the perspective of family and/or friends. I do not think that one necessarily has to visit a doctor to determine whether one has an addiction or not. Especially a gambling addiction. Not only would you be wasting a doctors precious time but you will probably be laughed out of his office.
The safe bet is: if you start asking yourself if you have a gambling problem, the answer should be an automatic yes, based purely on the act of self-questioning. At that point, just walk away from the gambling world for a few weeks at the very least. Some would even need a longer time to get rid of the gambling addiction.
People who easily get addicted should not gamble at all.