I’m unreasonably hurt after rejection and need help getting back to normal quick

I’ve been literally having dreams about this girl for six months, and I finally work it up within myself to ask her out, and she said yes, but at the end of that first date, I got friendzoned. I’ve been rejected countless times, I’m not a super attractive dude, but this one hurt so much more than anything else because she’s been on my mind 24/7 for the last half of a year.
I just started a new job three weeks ago and can’t really afford to let this drag me down, but my god it is. I’m sitting at my desk and all I can think about is how I would wait for her to respond every day at work. I’m getting nothing done.
Any ideas on some quick help?