First, relax. Much of what you are talking about is completely normal. Despite what you may see in the media, lots of people don’t find someone to love until into their 20s or even older. Not everyone is having sex. Not everyone can swim either. It’s also not unusual for young people between the ages of 17 and 25 to start questioning what their parents want for them. It’s part of finding your own identity. Sometimes people go in an entirely different direction than their parents wanted. Sometimes they end up choosing what their parents wanted after all — but now it’s their own choice as well.
I encourage you to talk with your friends about some of this. Often it is peers who can reassure a person that, yes, they are going through some version of the same thing. Instead of distracting yourself with pointless reading and being on the Internet, I think you should be experimenting with different activities to see what you like. Join up with a team, a club, a cause or an arts group. You won’t figure out what you do and don’t want to do unless you try some things. If not being able to swim bothers you, get some lessons. You can learn. Most people do.
The antidote to your state is to get active. Nothing is going to fall from the sky to change it. You have to. So, please get out of your room and into the world. Try out some things. Talk to people. Give yourself the chance to find out who you really are.
I wish you well.