Please help me, I feel horrible.?

I feel like ****. My 18th birthday is tomorrow (3rd) and I will not be doing anything. I haven't had a real birthday, cake or anything since I was 15. All I want is to hear happy birthday from my ex who just broke up with me, is that a bad thing? Why the hell do I still care? Why do I feel so bad still? I’m letting him ruin how I feel about my birthday..or maybe it’s just because whatever I do won’t be as great as what we could’ve had. I just feel bad because he promised we'd spend that day together, and now I know that's impossible since the plane ticket is canceled. He let me down. What the hell do I do? Please help me out here.