My gf said i'm toxic.

my (26F) gf (26F) was in the mood to fuck last night but I didn't want to have sex. I told her I wasn't in the mood and she was so angry, she kept asking me to have sex and I told her no but she said I was being mean. She said I'm toxic for not fucking her and I don't know if I was being mean or not. I don't want her to be upset because she's really pretty and I'm probably the only one who will love her.