Problem logging in wordpress.com

Okay, so its quite complicated.I will start from beginning.My wordpress site https://lexiocnhub.tk stopped showing my facebook like plugin, which actually was offered by Jetpack and i was using the widget. I posted the problem in forum and I was asked to deactivate the Jetpack and then activate it.I did.Now, when i tried to activate,it asked for my wordpress username and password.I forgot my username but anyway I tried resetting my password and I did that. wordpress.com signing in asks for either username or Email id and password , so .since I know my ID i tried to sign in with it but it gives me error.So, now I am left with my Jetpack deactivated and not able to sign it to reactivate it.Though I know my ID and Password , but I don’t remember the username but since wordpress.com sign in form asks for either of them I suppose I should be able to login.
Please help.Its important.