should I cancel plans with my friend? I feel so bad

I've had OCD and panic disorder my entire life, I'm 21 now. it's been pretty bad the past couple of days, but one of my really good friends spontaneously invited me up to her beach house (about an hour away) this morning. I really want to go but I was up until 4 am last night until I finally took my anxiety meds (they knock me out) and woke up to her phone call at 9:30. I feel sooo sick, and I know it's just from my anxiety. I just want to get over this but I'm so scared. I broke down crying because all I want to do is just be able to go to the beach and have fun but I'm sitting here on my bathroom floor trying not to puke. I don't want to cancel but I also don't want to go if I feel like this. I hate being a flake. I feel like I just need to reset my mind but I don't know how. what should I do?? am I a shitty friend for cancelling?