Hi dear. Some people of your age do face these types of problems. You feel that you trust everyone so easily and so people cheat you right?  Whether you trust anyone or not , cheating happens commonly. At some stages you should be able to think that cheating was done to either make opposite person happy or  to make u happy . I won't tell to accept the cheating people . Instead you she take the people and throw off their cheating situations. It means take good things and leave bad ones. You need to trust people and ur surroundings till the end of your life. So don't behave rudely or question people with doubts. Accept living with people socially and dont quarrel. Change your mind. Start a new life from today. Develop trust in all things. Think positive. Dont feel inferior. Nobody will change for u. But if you change people will be more close to u. You be a person where all friends can trust u. That's remarkable change. To still throw out ur low confidence and loneliness and diagnose your problems you can meet a counsellor once.