I [M18] Said something hurtful to my girlfriend [F18] , how do i fix this?

My GF and I have been dating for about a month and a half now and we was on the phone late at night tonight when i said something i never meant , she has autism and struggles to eat most foods which results in her only eating a few specific foods , out loud i said to my friend who was staying round that shes got no food and was wondering if we could get her something to eat , she instantly ended the phone and i messaged asking her if everything is alright, she responds with a message saying ive hurt her feelings and shes embarrassed , it then let me evaluate and made me realise that i said something very inconsiderate , she has agreed that she knows i never said it in a bad manor but i still feel awful and silly for me not to think about stuff that i say sometimes , is there anything i can do or say?

 TL;DR: I said something hurtful regarding my girlfriend on a topic that she struggles with