Yes, everyone will react differently to medications. I used to be in BCPs for about 15 years. My OB switched me from something to Yasmin, which is very similar to Yaz (Yaz is lower dose than Yasmin). I LOVED Yasmin - it didn't make me retain water, and I had no issues w/ my mood.
3 years after I had my DS, my PMDD just got the best of me, so I gave in and asked my new OB about it. It was either an antidepressant or a BCP. I decided on BCP because I've been on antidepressants, and I didn't think it helped much with my mood. She gave me 3 mths samples of Yaz. The second day, I was more irritable, moody, weepy, and sooooo miserable!!!! I know you're supposed to try it for 3 months, but I could't take it anymore and stopped after the 3rd day.
Pregnancy changes your hormones, as well as being in your 30s. So give it a try and see what happens.
There's also a low-dose Prozac, Sarafem, that's supposed to help too. You take it right after ovulation until your period starts. I found that I've been getting irritable no matter what, so I've been trying antidepressants. I loved Lexapro but SSRIs makes me wake up at the crack of dawn. I've been on Wellbutrin for 2 weeks, and so far so good. It takes a while for some of these meds to work, so try it out for a month or so.