That's right, evorel conti is a fixed dose, you can't easily increase it - you can wear two patches (this should be discussed with your doctor not done alone) but is not what I would suggest for the issues you describe.
First of all are you fully postmenopausal? If not this may just be due to your own ovarian hormones fluctuating.
If you are, then bleeding that occurs in the first 3 months of a new regimen doesn't usually require investigation as it is likely to settle by itself.
Another issue that can cause bleeding and symptoms of hormonal dysregulation is patch loss or dehiscence.
If they are not sticking very well or coming off, this results in inconsistent delivery.
If you are sure they are sticking properly I would persevere for another month or so. Do you have a review at 3 months?
If you still don't feel right on it after that I would discuss other options with your doctor, as there are many of them.