were you getting any protein in the last few months? fruit is wonderful nutritionally but certainly not complete. when you resume eating, be sure to include some good quality proteins.
i am concerned by your statement that you have already had 3 L of water and are still thirsty. i don't think you should be THAT thirsty, when you aren't sweating and expending a lot of energy. it is absolutely possible to get too much water. there is plentiful info about over hydration on the net. also information about excessive thirst. then again, your body may just be crying out for hydration if you were not getting much before (hard to believe on a raw, fruit filled diet.)
you can reasonably expect to lose 7 or even 10 pounds on a week of water only. most of that will be "water weight" and will come right back when you resume eating, especially if you are eating a lot of carbs. a raw diet probably doesn't include a lot of junk carbs, so you are probably safe there.
i personally find distilled water to be unnatural and unappealing, but MANY here swear by it and will be happy to give their reasoning about it. but it is important to have good quality water. your filtered water is probably fine, IMO.