I'm not going to buy my girlfriend weed during her panic attack
Can she buy it herself?
She's not feeling well and she's in no condition to buy herself weed.
Taking care of people can be draining but if she can't do it, you should take care of her. She will appreciate it when she feels better.
You are trying to think for me but I know what I should do about my girlfriend.
You do know your girlfriend better but she knows herself more. If she  thinks she needs the weed, then you should support her now.