Tea + caffeine HELP

I know this is a really random post but I need some help/opinions.

So i just drank about 2 cups (about 16 oz) of black tea about 1 hour ago. Well i didnt know that black tea had caffeine in it until i got a headache about 25 min later/30 min ago. I always stay away from caffeine because it makes my anxiety worse so now I'm kind of freaking out trying to get this caffeine out of my body. Especially since its night time and i want to go to bed soon.

Not sure exactly how much caffeine is in black tea all i know is that i used a keurig to make it. Does anyone know how to get this caffeine out of my body quickly?? My head is killing me from the caffeine rush right now. :(