I think there are a couple of things going on here. One, yay for the tumor markers! I'd be estatic over that, but that's because mine always go down when treatment is working. Your miles may vary, but for me, that's cool news.
As for the rising alk phos level, when your doc gave you the numbers, did he/she not go over what they meant and if it was cause for alarm? Your doctor should clear all that up for you, and if you get labs that you are concerned with, don't hesitate to have the onc clear them up before you leave the office - that feeling of just not knowing what is going on is awful.
What I picked up on immediately was the end of your post, indicating your frustration with the "ups and downs" of this disease. I understand how you feel and wish there was an answer for you on that one. Because CC is tricky, and treats everyone and every treatment a bit differently, it's so so hard to predict what will happen. Rejoice in the fact that you've made it so far past your prognosis. It'll take a while to "get used" to the disease, and understand that there's more than just beating or succombing to cancer. We're living with cancer. It's just a part of our life, and we deal with it. You're not doing anything right or wrong. Have you a strong support system to help you through these times - or even a therapist or social worker that you can speak to? It's good to get these feelings out!
Therefore do not worry about tomorrow, for tomorrow will worry about itself. Matthew 6:34