Stop telling people that you are sorry for bothering them, stop giving and expecting, instead be yourself and with little acts of kindness, conversations developing into more deeper and personal topics over time, your initiatives to show that you are trust-worthy and a happy person, you will make friends.
Before being a good friend to others, we need to be good friends to ourselves.
Monkey was right, finding a hobby will help, sharing your passion and interests with like minded people definitely will give us more opportunities for creating friendships and what I have learned the hard way is that if we won't approach people, they won't do it either, because they will not know how we are and whether we want to be their friend, if we're always sitting alone and not engaging with anyone or anything.