Is it normal i fake friendship?

Throughout my high school years I was a very popular person. Everyone new me, I was well like to an extent, and never got into any drama. I had alot of 'friends' and I was the go to person to confide in. People would always come up to me for advice or to vent their feelings. I knew everyones secret, was up to date with nearly everyone.

I was very friendly and a jokey sort of person, never took anything serious and because of that everyone loved to be around me for a good laugh. I wasn't scared of embarrassing myself if it meant entertaining people (I wasn't a class clown though, usually I didn't talk at all in class and did my work)

Despite that I've always felt lonely, and never wanted to hangout with my 'friends' outside of school. I'll admit I find it fun to be around them, but I never really felt any strong attachments or emotions. I just wanted people around me so I wasn't alone during break so people wouldn't look at me or stare if I was alone.

It felt easy for me to make friends because I feel like human emotions can be extremely easy to manipulate, it was easy to feed the people around me with fake praises and talked about their strengths and made them feel special, like they were the only person in the world that I cared for.

I know its bad and I did really try to invest actual emotions, I liked them but still never really cared for them. If one of them were to die I don't think I would care and I understand that makes me a horrible person. Sometimes I would get annoyed and fed up with my friends and think about different ways of murdering them.

Does anyone know how to actually feel emotions properly? Do I have to take medicine to gain human empathy or will I be stuck like this?