Hypertension. After that i m worried!

I m taking Aten 25 tablets since 2 years. Couple of days back I went to the doctor for treatment of diarrhea. He checked my BP and it was 180/110. Actually I have "White coat Syndrome " when doctor told me that she is going to check my BP, suddenly I had extreme palpitations. And after she checked BP, again heartbeats got normal in few minutes. She took only 1 reading. Before that I checked my BP 8 months back, in my home. 1st reading was 158 (systolic BP) & 2nd reading was 139 (systolic BP). Couple of days back, before going to doctor, I was feeling normal but after that I m worried regarding my health. She told me to increase the dose of Atenolol to 50 mg. Should I increase the dose or please suggest any other good anti hypertensive medicine. My age is 28 years. 2 years back I did echo test, ECG test. All reports were normal.