I'm the same, I have 1/2 runny weetbix for brekkie and ony the last two days have I been able to finish it all, until then it was 2-3 teaspoons. Then I have yoghurt 3-4 teaspoons as well as some casserole pureed at night again 2-3 teaspoons, I am struggling with water as well.
Yesterday I made a soup/puree of tinned tomatoes, shredded BBQ chicken and red lentils, cooked this down and I have been able to eat 1/3 of a cup so I am sticking with this today.