When I got to the part about it going solid in the glass i am just about certain that this is psyllium fibre. You may find you can buy it a lot cheaper as psyllium fibre. Its also used in a product called metamucil which you may have heard of.
Anyway, I want to add a few other things.
1. don't get panicky about not losing weight the way you expect to. You are doing a lot of exercise and probably building quite a bit of muscle which you must know is heavier than fat. This would make sense if you just started doing your exercise very recently.
I'm your height and a weigh a bit more. I think you might find 1200 calories is not enough for the amount of exercise you are doing. Havce you run your plan through a calculator to find out what is a good number of calories for you?
don't be in a hurry to lose it fast. Its not sustainable after you lose a certain amount so its better in the long term to do it slowly after the first few kilograms. I know we all want it off fast but i've done many diets over my life and lost it and put it back on again over and over again. Been fit, got unfit etc.
I have a good exercise for you to try when you are stuck at home. Don't laugh but buddhist style prostrations are very very physically demanding and don't take as long as walking. Though they can be hard on your knees. So put a pillow on the floor. Don't ask me how i came to make this discovery about how strenuous these. If i remember correctly it takes about 20 minutes to 100 full body prostrations.
To do them:
Stand up straight
Bend down and get on your knees, all fours.
Then learn forward into a sort of push up but not a pushup. You are just going to lie face down on the floor. Do not rest there even when you need a rest. Get up straight away.
Back to standing position.
If you need to rest, do it in standing position.
A yoga matt might be good enough too.
don't over do them because you might cause yourself an injury. I know a monk who was doing them for four hours a day or four hundred i am not sure which. He had to do 111,111 for the year, i think. so he worked out how many he had to do a day and suffered the results.
I think i have gone quite enough for now. I hope something of that has been useful and thank you for sharing your experiment.
don't be disheartened by anything i've said. YOu've started now. You should keep going.
Also ask your boyfriend not to eat sweets in your company. Since its your house you could probably get away with a request/rule like that.