getting tummy ache the past two weeks

[Ohnonotagen]

i lost my first half stone in first five weeks which i was pleased with as that included a week on holiday. I lost around 1-2.5 pounds a week

then last week i started getting tummy ache, i'd been eating quite alot of lentils so i thought it was trapped wind and got some tablets to take, ended up putting on a pound last week, although i hadn't been 100% on it all week.

then yesterday i had mushy pea curry and since then i've had terrible tummy ache again and feel really bloated

i'm eating plenty of other fruit and veg. Maybe i'm not drinking enough water?