Yes, that’s right there is plenty of fishes in the sea. Whenever you meet, see or go out with someone and it doesn’t turn out well, don’t worry there are plenty more out there.
Truely, there is plenty of them out there and you don’t have to worry about it. Especially at pubs/bars as girls get approached 3-10 times a day and they will probably not remember you the next day or the next week.
And you should take advantage of this to practice building your confidence. Just give a small wink and a slow smile to random girls, if you are unable to talk to them. Even better a quick and small wave while keeping eye contact.