I Just Started Taking Atenolol Thursday, 25 Mg A Day.

I just started taking atenolol Thursday, 25 mg a day. My heart is good, did and EKG and Echocardiogram, blood work and blood pressure and all is good. I have high anxiety, so my heart will race or pound sometime and it's gotten to where I panic more than I relax..so he put me on this medicine and it works very quickly, however I still panic, but my heart doesn't race so that's good. My question is this, can I takenthis med at night or cut it in half? I fell like I'm moving in slow motion and I'm tired. I'm a waitress and need to move fast. Also after eat my heart pounds and I don't know why, that started before the medication but I'm still at a loss as to why? Is all this stress and if so do I need a different medication for this?