My Family Doctor Has Started Prescribing My Atenolol For My

My family doctor has started prescribing my Atenolol for my high blood pressure in addition to Hydrochlorot--side question on this, is this the same as HZT, the water pill?--and I just read online that a, I guess a more serious side effect of Atenolol is the chance of a pulmonary emboli which I had in October 2015, but other than some slight scar tissue, I've had no problems--I am seeing a Polumnlogist on a regular basis--but seeing this has me extremely worried---my family doctor, of course, knows about the blood clot---I've already taken my dosage for the night--should I be worried beyond normal, like should I go see my family doctor in the morning first thing..or am I okay?