Is my Nurse exagerating saying I have way too high blood preasure? It's 140-something /over/ 90-something?

As long as I can remember everyone's (doctors/nurses/blood drive people, etc) have said I have good blood preasure... but I never thought to ask for the numbers or anything, I don't even really know what's normal... what's pable... risky... etc. But when I went in for my birth control shot a different Nurse then my regular one saw me and said that she was concerned and that it was like 142/92 (giver or take a couple points) and that if it goes any higher it was very bad & i should see a doctor-doctor. This really suprised me. I'm a white, 24-y-o female, don't smoke, walk more then most since I haven't had a car in a few years and use the buses... I am a few pounds over what i "should be" according to those evil height/weight charts (6ft0in - 200lbs +/- 10lbs depending on what kind of week i've had). But roughly a year and a half ago I started at my current job, which i almost always really enjoy (press operator for newspaper) so ya, there's a bit of stress & physical exhaustion added but she said my BP (the lower number) was in the 40's and it's been steadily increasing up to this point. SO - is this just cuz I eat foods like a teenager/20-something year old and should "take better care of myself" or is this a possible Red Flag? She couldn't tell me anything diffinitive w/o running tests she can't do or some legal reason... but just said I should be checking it weekly and if it goes any higher at all to see a doctor, which I think is just silly... I feel fine. Any Knowledge Would Be Great! ~~Thanks!