Help! Not feeling up to travelling but I don’t want to let people down

Hi, I was wondering if anyone here had any advice or could at least relate to this. I was gifted a weekend to amsterdam with my boyfriend next month. 

I due to my autism find travelling quite distressing and overwhelming. I don’t really want to go but I feel I have to, otherwise I will disappoint my boyfriend (even though I never asked for this trip and have explained and he has seen first hand various times that I find travelling too overwhelming most of the time).

I also don’t want to go because as much as my boyfriend tries to be understanding and not pressure me, he doesn’t understand autism and how difficult these things are for me no matter how I try and explain it, and how physically exhausting they make me. I am also scared of feeling the pressure of having to be out in public sightseeing the whole time, when I can’t do that without then going in to burnout and feeling awful for weeks. 

Do I go and mask to not disappoint him or do I look after myself and not go and prevent feeling completely overwhelmed and burnout? 

Im stressing so much every day and not sleeping well to the dread of this trip even though it’s 4 weeks away