Your reaction to her marriage to another is understandable. First, you must be upset with yourself for delaying when you now feel you should have acted. Second, she must seem more attractive now than she did, when you were delaying. Perhaps you were thinking she would wait for you until you got around to moving forward.
The best thing you can do is learn from this sad turn of events. Do better next time, but do not be hasty and make the mistake of marrying on the quick rebound of your disappointment. Your reaction does not seem to be an illness, only a sad disappointment from which you can learn a valuable lesson about life.