Is it normal to gain weight before and after my period?

I usually manage my diet well and exercise consistently, but I am worried because my body suddenly swells and I gain about 1 to 2 kg as my period approaches. I haven't eaten particularly much, but my body feels heavy and my belly seems to have gotten bigger, so I get anxious for no reason.

Especially before my period, my appetite increases more than usual, and I constantly crave sweets or carbohydrates. Whenever this happens, I get stressed worrying that my diet might be failing. My weight does gradually return to normal once my period starts, but since this happens every month, I wonder if it is a normal phenomenon.

Is there anyone else who experiences weight gain or swelling before and after their period like me? I am curious whether the weight gain is actual fat or just temporary water retention. I would also like to know if it is better to maintain my usual diet during this time, or if it is better to manage it a bit more loosely.