Jealousy can be normal.. But bit can also be damaging and dangerous to yourself and to others.. So be careful in not turning that jealousy into hatred.. Cause you'll just end up more miserable than you are now, plus you could end up doing something really dumb that will not resolve your issues and only make them worse.
If you have high standards, the girls you are after more than likely also have high standards.. So if you're not living up to your expectations yourself, then you'll have to rely on luck and hope that something happens with someone..
Anyway, I would never go to a restaurant by myself.. I never understood and still don't understand why people do that... It's sad and scary...
And if you have mental problems, why don't you seek help? Therapy of some sort, someone to talk with.. That can help you, and it doesn't necessarily have to be a professional therapist... Or maybe a psychiatrist.. I don't know.. But get the help somewhere!!