That's the only problem when you do low carb for a while and then eat carbs, the water just piles on. My body much prefers low carb, but I know I cant stick to it for any longer that 4 weeks when I have a carb fest and then pile the water on, get pi$$ed off and then end up wrapping it in and stuff my face for about 3 months. Water weight does make you feel bloated, that's probably why you feel 'fat'.
Have you tried doing low GI/GL, where you can still eat carbs but they all have to be whole grain, such as wholeweat pasta, brown rice (personally I hate brown rice, but there you go), wholemeal bread, oats and the likes? That might suit you better?