Hi. My Doctor Placed Me On A Water Pill (hydrochlorothiazide)

Hi. my doctor placed me on a water pill (hydrochlorothiazide) recently and I noticed that I gained weight and now have a bloated tummy. Are these side effects of the medication? Also I just changed my diet recently by including whole grain cereals and bread in my breakfast items. I am just wondering if bread/whole grains cereals can cause bloating/weight gain. Thanks