First off, think long and hard about which ones you think are your true friends. Set up a place where you all have connected in the past. I know it sounds stupid, but it might be a wanderful experience. I can remember a place that all my friends used to go swimming at. Im 25 now, but I still remember saving my frend after he jumped off the crows nest (TOP OF THE TREE VERY HIGH) when we were 14. Then, after you beat the cancer and are stronger because of it, you will also know who your friends are. You will become so much stronger because of this. Please dont ever give up. You can handle this, and you will perservere.