You're being way too hard on yourself. It's actually a good thing that you're single at your age - it means that you've avoided having your heart broken.
May I suggest that the first question to ask yourself when considering whether or not to date someone is, “Is this person a strong person?” If they’re not, no matter how much you like them, how much they like you, or how “cute” or “hot” they are, - please don’t date them. A strong person has good character (honesty, integrity, trustworthiness), displays a positive attitude (cheerful, caring, friendly, forgiving, helpful, and respectful), fulfills their responsibilities (for handling pains in a positive way, for always trying to make a good choice, for taking care of themselves, for serving others), gives their best effort, and demonstrates self-control (of their body, anger, mouth and money).
My suggestion is that you put in the effort necessary to become a strong person (if you’re not already) and eventually look for this type of girl (otherwise you’re setting yourself up for a broken heart). Unfortunately this type of woman is difficult to find - but save yourself the heartache and don’t settle for less.
(Please remember that you eventually want a 50 or 60 year marriage - not a 5 or 10 year marriage.)
Hope this helps!
PS Here are "21 tips that could help you to attract a strong person" from the book True Love Lasts:
1. Take the time and put in the effort to become a strong person yourself (this is the most important tip)
2. Put yourself in as many situations as possible that will allow you to potentially come in contact with other strong people - community service organizations, the library, high school or college clubs, the “Y” or other workout facilities, religious book studies, coffee shops, non-alcoholic parties, bookstores, concerts (wear a good pair of earplugs to protect your ears from permanent hearing loss), co-ed recreational athletic teams, community service projects, mission trips, volunteer service, etc. Try to get to know other people as much as possible without dating
3. Be cheerful, approachable, and friendly - smile regularly to put others at ease (let people see your positive attitude)
4. Take a real interest in getting to know others. Ask people an open-ended question about themselves in order to get them talking. Share things related to what’s been said as needed to keep the conversation going. Then ask them another question
5. Be polite and kind to everyone - even to people who you don’t like or enjoy being around
6. If you decide to not accept a request for a date, do it in a kind way (being rude isn’t a good choice and it doesn’t help you - word about it will get out and you’ll become less approachable)
7. Be confident about yourself - if you’re trying to become a stronger person each day, you already have a lot going for you
8. Be humble - don’t act like you’re Miss Charming or you’re Mr. Wonderful
9. Don’t be concerned about whether or not someone likes you
10. Have the attitude that if someone doesn’t like you - they don’t really know you
11. Take care of yourself by getting enough sleep (at least nine hours for teens, at least seven hours for adults according to the experts), exercising regularly (if approved by your doctor), and eating a healthy diet
12. Develop a good sense of humor - including the ability to laugh at your own mistakes
13. Be known as a hard worker
14. Dress well and dress modestly at the same time (wearing seductive clothing doesn’t attract another strong person)
15. Pay attention to your appearance, but don’t obsess over it (remember that strong people are attracted to other strong people, they’re not too concerned about looks - because they realize that looks fade with age). If you use makeup, make sure it’s not excessive. Use perfumes and colognes sparingly - if at all
16. Truly care about other people
17. Stay in close communication with real friends who can help you through the ups and downs of life and hold you accountable
18. Be patient - real friends can help you with this
19. Persevere - please remember that almost nothing worthwhile is quick and easy. Please don’t settle for dating a weak person
20. Don’t take it personally if someone doesn’t want to date you
21. Don’t act desperate for a date
PPS Depression can be very serious. It sounds like you might need some professional counseling to help you talk through this. It's often available for little or no fee through health insurance. Almost everyone needs counseling at some point in their lives.
True Love Lasts - written with a character emphasis for teens through young adults,
Straight Talk About Dating - written with a Christian emphasis for ages 20 and up