How can hypertension along with elevated cholesterol levels and headaches be treated?

I ve been suffering High blood pressure (BP) for several years now along with High Cholesterol too. I ve been taking Losartan Potassium 100mg and it has controlled my , Until a bit over 2 weeks now my Blood Pressure has been on the pretty high side 160/101 which is causing me headaches. I went in to see my doctor about my concerns and he added Hydrochlorothiazide HCTZ 12.5mg in addition to the Losartan Potassium 100mg; both medications together have taken my BP down to 138/94. However, my BP goes back up after a few hours. I happened to be in the hospital on Friday into Saturday morning for the birth of my Grandson and my pressure shot up while I was there to 164/107 and a Headache to follow. I went into the ER at the Hospital, they did a CT scan, EKG & Blood work all of which was normal; they could not explain why it was happening. They gave me 0.2mg Clonidine & Tylenol and my pressure went down to 132/82 there about. I contacted my doctor the next day about the results and I was advised to take another Hydrochlorothiazide HCTZ 12.5mg, it s a low dose so I can take it more often when needed if my BP goes up again . I have been doing everything the doctor & hospital has told me. I have a pretty good diet fresh fruits, salads, low carbohydrates, very low sodium and I drink plenty of water, about 60+ozs a day, I have changed from regular coffee to decaffeinated last Thursday as well. Does anyone have any suggestions PLEASE, I m afraid that something bad is going to happen to me where I won t wake up if I go to sleep! Thank you in Advance Melanie