I find it extremely difficult to go back to those whom I had stolen from, nor can I ever confess to them in order to gain their forgiveness. What should I do?
It is not necessary for you to face the embarrassment of informing them yourself, or offering compensation in person. You can send their dues to them by, for example, mail, or through another person without revealing your identity. You can also place it in their sight without their knowledge, or say to them if you have to go in person that "someone" - who doesn't like to reveal his name - says this is your property. In short, the important thing is to return rightful property to the people who it was taken from.
And Allah knows best.