I was in the same boat as you till I met a wonderful open minded girl who saw something in me which I didn't even know was there. So my advice is to just be patient and try to keep yourself from becoming a bitter person. Before I met my girlfriend I to used to feel sad, irritated or sometimes even hateful upon seeing couples holding hands at public places. I learnt to force myself to not look at them at all. I kept my head down and kept myself busy in various things apart from work. It worked for me as my mind became more free and I could use it for more useful things. And I kept trying my luck at online dating as I am too shy for social gatherings. Be aware that the online dating scene can be too draining and can put you in even worse mood. So my advice is to use it in controlled measures.