What is wrong with us?

I've been in a relationship for 4 months now with my girlfriend. We're long distance, and met for the first time last week. Everything was great, we had great chemistry, physical contact, and kissing was amazing. The second it went any further.... things got tricky. She had been with girls but never done oral sex, and I was essentially her first time. She did it, but didn't seem to enjoy it. Afterwards, when it was my turn to get her off, I couldn't do so giving her oral (fingering her was not an option due to having fake nails on). Eventually, she let me use my fingers to rub and got off, though she said that it made her feel like she was doing it.

Ever since then, she has been off with me. I went back 2 days ago and have had nothing but coldness. Finally, we had a conversation about it and she said she's worried that there is something wrong with her. She said she loves me, and is attracted to me, and enjoyed fingering me, but giving oral made her "feel like (she) could throw up". She said she hated the wetness and the texture on her mouth. She also said that she didn't find sex enjoyable. I asked her if she thought it was because she was straight and she said she thought about it, but she's sure she loves me and is at least 5% gay, and that is enough to love me.

I'm really worried she is actually straight and doesn't want to hurt my feelings. I'm also worried that it's me, and I'm not good enough (I've had experience before with no issues) or that it's that she doesn't find me attractive. She insisted it was neither of these things. I don't know what is wrong or how to move forward in the best way to help her and make her comfortable again. I don't know why she isn't enjoying sex and if fingering her would have changed things. Because we're long distance, it's difficult for me to try and fix anything as we won't see each other for months.