I am a 37 year old female and was was started on Atenolol .25 mg 1x/daily for rapid heart rate due to anxiety issues yesterday. I also take .5 Xanax as needed. I'm feeling a little light headed today and have diarrhea. Is this normal when starting this med? I had an AWFUL reaction to Zoloft, so now I'm super leery of trying new meds. Any info/feedback would be greatly appreciated.