Diovan and lisonpril

I was on Lisonpril for three months, then switched to Diovan due to the cough caused by Lisonpril...but at least I could read that side effect in the prescription warning. There was no warning of weight gain with my current prescription of 1/2 pill a day(180mg). I have been on Diovan for three months and have cut caffeine and increased my exercise. At first the drug lowered my bp from 150/102 to 125/85 which I thought was great..but my bp has been slowly increasing. I started at 130 lbs and am now 150lbs...I have gained over 20lbs since starting the drug. I've experienced painful gas and insomnia. I am only 41 and two flights of stairs and I'm out of breath. A drug you take to make you feel better shouldn't make you feel worse. I'm going to try to use more natural methods.

after starting Diovan HCT 160 mg. it reduced my bp from over 150/90 to around 120/76- this went on for about a month, but now my bp keeps creeping up again to over 138/85 or 145/88, etc. But I have no side effects.
why is that?