Desomono pill and discomfort wearing contact lenses

I was put on this brand after my GP said my prescription was put on a generic where chemist chose what ever brand they have. I'd been on Cerelle brand for over 5 years and this brand isn't suiting me. I've only been on this brand a month but I'm experiencing stomach cramps, irregular periods. Where before I wasn't seeing any period unless I accidentally missed a tablet. I'm feeling very tired and low in my mood which has effected my sex drive. I'm having headaches also. I have researched this brand and I've read other women have experienced these side effects. I'm contacting my gp to arrange a consultation on this as I want to be back on my previous brand my body is used to taking. I'm hoping I can as I'm not feeling well taking this.