I am so sorry you are having a hard time of it choc, but it should get better.. You can have your shake hot.. You can experiment to suit your tastes.. Some people put coffee in their vanilla shake, others put peppermint tea in their chocolate shake... Has your pharmacist not given you any advice at all hun? If not, ask on here cos someone should always be able to answer it.. I have had problems with constipation, and i have taken senakot (although it got so bad at 1 point, i had to get suppositories from the chemist)..Please keep an eye on your bowels as it can turn out to be pretty bad... To keep me regular i use psyllium husk every other day.. Your chemist can get you some Fibreclear from LT (around £4.95 a tub, but it seems hit and miss whether it works or not)...
Would black coffee or tea help you? You can also have any LEAF tea (eg nettle, peppermint, raspberry (make sure it is raspberry LEAF though))... You can also add sweeteners to your shakes/drinks as long as it is in tablet form....
If you still feel like this at your next weigh in it might be worth mentioning it to your pharmacist hun... Good luck x x