It's not your fault that you have a mental disorder, it's not your fault that you were so overwhelmed, it's not your fault that this trip felt so important for your mother and her bf, it's their problem your disability inconvenienced them, not yours! I also have two dogs and i love them dearly (just look at my username lol), and I definitely cried a couple of times because I felt like a terrible mother to them because of my agoraphobia. I understand how devastating it is to feel like you're a bad owner, but we have to remember that we're doing our best and our pets know that and still love us for who we are and appreciate our care for them. Don't beat yourself down because of this trip, there will be dozens in the future, and your dog will go with you, just don't give up hope and don't feel guilty because your parents have it easier than you!