Let me respond to your last sentence, first. Too many people proposing to you could be because you may be a cheerful person, make your presence felt, make people around you happy, or you may be attractive/good looking. Irrespective of the reasons, it would be good in your own interest to keep yourself away from such relationships as this is definitely not the right time or thing to do. Between the age of 12 & 20/21 years, it is the time to make your foundation very strong, in terms of mental maturity, physical growth and financial stability. For which, now your concentration and focus must be on your education, next step to qualify, aspire for a good and stable career that provides you financial stability, status in the society and confidence. Feeling of loneliness, trust me this feeling will make you feel worse. Blaming yourself for how you are feeling will never make you change or help you to be productive. If you are feeling uncomfortable being around with humans, there are other ways to seek relief from non-human friend, that is go for a pet, read favourite books, involve in physical activities such as jogging, brisk walking, gym, swimming, indulge in writing stories or poems etc. This will surely make you find solace that will ease out your loneliness. The next step is to connect with human friend, if you can. Think of someone who have been supportive or who will atleast make you feel good and make you laugh. There is no age barrier (don't have to be with homogeneous people, it can be heterogeneous too). You may resist doing this at first because it can be hard to reach out to others when you’re feeling lonely. Give it a try, which will help you to connect/contact people whom you can count on. You can talk to your parents or elders who were supportive and tell them how you are feeling. Visiting a Counsellor will help, as the counsellor can empower you to systematically handle these unwanted thoughts, manage anger and help you remove the extreme step thoughts. Life is simply beautiful, you choose to either enjoy unconditionally or keep worrying about things which are beyond your control. You have a very very long way to go in life. Seek help and move ahead. God bless.