I have been taking Atenolol 12.5 mg for two months, not tolerating it well - dissiness, lightheaded, confused, etc. My dr. put me back on Valsartan, which I had taken prior to Atenolol. I stopped Atenolol yesterday and replaced it with Valsartan 80 mg today. Now I the above side effects are even more pronounced. Should I be concerned? Should I stop Atenolol gradually and then get back on Valasartan? Thank you.