Flying tomorrow?

I have received an email reminding me of my flight tomorrow to Washington DC. I can't believe I booked a flight for 21 April instead of 21 May. I'm trying to change it online but my details aren't being refreshed on the wesbite so I may have already changed it but I can't tell. Very frustrating. It was a cheap flight with their equivalent of Jetstar, so if I do lose some money it's not a lot. Hopefully the site will eventually tell me that I am now rebooked for May.