All of my friends, including my girlfriend, and even my family think its wrong for me to hang out with my girl bestfriend. Any advice?

They think its weird how much time we spend together and we in no way have any physical attraction. She often has panic attacks and at any time she'll ask me to hangout to be there for her. All of a sudden tonight all these people have been texting/calling me telling me its wrong how we can spend all day together. What should I do?

EDIT: Thanks for all the help guys. I think I'll just have to hang with my bestfriend less since I would rather not piss off my girlfriend.

EDIT: My friend does see a therapist. She's just clinically depressed and I am literally one of her few friends.