Being young is not always easy is it! Speaking as a woman who is much older than you I am sorry you are feeling like this! There seems to be so much pressure on young people to engage in sexual activity now.
You are only 19! That is so young. I don't know if you are studying or working and I'm sorry you've had an eating disorder to deal with too.
Take the pressure off yourself. The other people are probably bragging about things they've never done and know nothing about.
Why not wait for a fulfilling and meaningful relationship with a girl? I don't think casual sex is very meaningful myself.
Heaps of people older than you haven't been in a relationship yet. There is absolutely no shame in that! There is nothing wrong with pursuing your studies or job and I'd concentrate on having some good friends of either sex. Get used to enjoying being with people whose company you like, both girls and guys. Are there some interests and hobbies you can participate in with other people? These can be a great way to meet other people.
Try to get to know girls and young women as people first. Enjoy having them as friends.
There is plenty of time to meet someone you really care for and who cares about you.
I honestly hope you know that it's perfectly normal not to have had an intimate relationship at your age.
You sound like a good young person. Don't be in such a rush and stop feeling inadequate. You're not!
Be nice and friendly with young women. Treat them well. Be a kind and good friend to them.
You will meet the right girl for you one day.
Don't worry about what other people do or don't do. Do what is right for you.
Above all, be kind and respectful of women. They will appreciate you for it.
You will be fine. 🙂