Congrats on making the decision to sleeve! I to have the same surgery date of 4/15, and like you I have to be on the two week liquid diet to. I guess because it will shrink my liver.
Day 2 was CRAZY for me, I was so hungry! but day 3 was way better. Im on day 7 now and just putting my head down and pushing forward. No I'm never fully satisfied with the shakes, but I know I can do this. Like someone else said on here, pressing on to keep my eye on the prize!
I find that sugar free popsicles really help and if you eat a cup of jellow before a shake, that helps me to feel more satisfied. Anyway good luck!