I feel lost and empty....again

I was speaking to somebody for a while going far to well for me flirting, nicknames telling me she wants to be with me lost night saying she wanted to be in a relationship with me and is in this for the long term, it was getting serious. Then on Thursday night by accident i seen a picture she was tagged in on Instagram where shes dressed up looked really nice with some bloke and in bed cuddling on the other picture. Turns out shes been in a relationship for half the time we was talking and didnt think to tell me and wasted my time lied about all sorts it seems mow but she told him not to upload any photos of them together so thats makes perfect ok right (sarcasm) brought it up to her talked about it didnt sleep at all through anxiety and being upset then blocked me on everything Friday morning been an absolute mess since. Im absolutely devastated about it i felt like id known her all my life the first time we ever spoke and its pathetic to feel like that about somebody who you never met but i part of me still wants to be with her and look after her and help her with her own mental health problems. This has kicked off horrible feelings again when it was the only things keeping me happy and not thinking horrible things.

Its the same situations different face. Im 27 been single for 11 years, never been on a date, not even hugged anybody in 4 years, spent most of my life on my own and im worried that ill spend the rest of my life on my own as well. I have nobody to turn to as everybody I know has never been there for me soni dont feel like i should talk to them about it.