Mocha is exactly right, slightly low might be normal for some people. It would be unreasonable to think of leukemia. You can worry if your platelets decline steadily, or if you had a reading under 50. Under 25 would usually be very concerning.
Side fact: My father had platelets measured at 5 (yes, five) from lymphoma, yet there was no bleeding.
The normal range for platelet counts for an adult is 150 - 350, however, I believe some people have their own normal which can sometimes fall a little outside of that range. You may be a little more at risk for not clotting as well, but if your doctor didn't seem very worried then you probably shouldn't worry either (especially if you don't have any other symptoms).