Why do I feel so lonely? I have many great friends who would support me but why do I feel this way?

Could understand. It happens even after if one have good friends and support system. Sometimes one feels lonely. Probably you could talk about it with your friend to recognise what causing you such feelings. Or maybe try to do some stuffs that interests you. Cause of feeling lonely vary from one to another. So, recognising cause could help to deal with it better.

Lonely comes from withing and often have nothing to do with external situations. If the feeling persists seek professional help.

You might be feeling lonely because you haven't found something that makes you feel empowered or happy about. Like for instance, try giving out your time to people what I mean by this is maybe try volunteering at a place you are interested in. This will help you feel less lonely since you are surrounded by others plus doing something good for humanity. You will get involved in many different types of activities and forget that you feel lonely. Volunteering has helped many people feel less lonely so trying anything that your interested will help you feel accompanied by someone.