First off, that girl sounds like she is super insecure and in the long run you will be thankful that things didn’t work out. Second, speaking from personal experience it takes time and space to get over someone — which, given the certain circumstances of the world right now, you have!

I would suggest you consider therapy or keeping a journal as I’ve found that to be very helpful. And be kind and show compassion for yourself. Take this time to better yourself and become the kind of person you’d want to date by figuring out your interests, taking on new hobbies, taking care of your health, and the big game changer for me— practicing gratitude, even for something as simple as having a roof over your head and food to eat, each night before you fall asleep. Set goals and dive into something new! I am not a doctor or a therapist but this all worked well for me and I hope it might work for you too :-) I’m sorry she has made you doubt yourself so much. It just speaks to her immaturity. You will look back one day and realize it.