I very recently started Cymbalta 60mg. Three months in and I have had no serious side effects. At first a few random mild headaches, but that was all. I have been on several different meds thru the years and most of them seem to have the brain-zaps as a withdrawal symptom. I believe that is your brain adjusting to the change. Of course there can be worse side effects and withdrawal issues, but I have had a pretty good experience so far.
Remember any time you start a new med it can cause increased depression or anxiety at first while your brain adjusts to it. These pass in a few days usually. Also other things going on in your life can affect your ups and downs. I would give the med 6 weeks (if no serious side effects) to really see if it's working well or not.
As always, get to ER or call 911 if you feel in danger of hurting yourself or others, meds or not.