People react differently to medication in my opinion, however there can definitely be side effects from these, but relating them to the medication can sometimes be tricky in my experience. I have taken medication with good results and I am convinced that when combined with counseling, it was the best path to take for me.
You said that it seems to work. For me, I balance the side effects with the results of taking the med. Since your panic attacks are happening less, are the headaches numerous and a reason that you cannot take the medication anymore? Or are some of the side effects okay with you now that your anxiety is much better?
What does your prescribing doctor say about this? Headaches can also be caused by an endless number of factors in my opinon. Are you getting enough sleep? Are you still under a lot of stress? The point is, that the headaches may not even be related to the medication itself. I know it can be very confusing and frustrating, but ultimately the decision to use medication and balancing the side effects with the results is a personal decision.
For me, finding the right medication took time and some disucssions with my doctor and pharmacist. However, I am happy with the results.. I believe having an ongoing dialogue with the prescribing doctor and your therapist is always a good idea with this....keep us posted!
you have the right to ask for a change in meds, also drink plenty of water stay hydrated ok :)