I am surprised you have had a problem with Yaz. . . I have been on it for 4 or 5 years and the only "problem" I have had is that my period has become almost extinct . . . My gyno said that as you get older (I am 3 years older than you) and because of the timing of the pill (only 4 days off), this is perfectly normal.
The weight gain is another issue, when I first started, I lost weight and it wasn't until the last 1- 1 1/2 years (1 or 2 years after starting) that I started having to fight the bulge again - which has by the way been a cyclically normal fight for me - every 5 years or so my body size/weight "shifts" for no apparent reason- so the loss might have been a coincidence.
Anyway, you might consider getting a full spectrum blood test to make sure that there isn't some other reason for your "side-effects". You might be that one in however many people who have a potassium problem when on Yaz.
Bottom line, if it doesn't do what you want it to do and you have tried it for a reasonable amount of time (5 months is getting close to reasonable), then talk to your Doc and switch if she/he agrees. . .
Good Luck.