remember that using a cuff that is too small will give an inaccurate reading. something as simple as comparing results when lean and in shape vs. off season can give big discrepancies if your arm measurements fluctuate.
you can really develop hypertension seemingly out of nowhere, for me it happened when I hit about 25. before that nothing ever made my bp high, weight gain, gear usage, or any other vices. then one day during an especially stressful period in my life, boom... 180/110 at the doctor's office. I have been on atenolol ever since, which I find helps me a lot as it has some effects on general anxiety levels as well, being a beta blocker. even though I live a much healthier lifestyle these days (dropped some mass, cut way back on drinking etc), I still require the meds to keep my bp in the normal range. typical reading for me these days is 130/85.
have a talk with your doc and see if it was a one time fluke, or something that you need to get under control. if caught early it really is not a big deal...good luck bro