Your results are low, but you're not far along. If it's under 100, they usually will keep testing you to make sure the levels are rising.
Well, if you conceived on the 19th, or close to it, you would still be almost 5 weeks, by almsot a week, going by the prior 2 week rule. I would not worry about it until you get your results back, and if you're still worried, ask your doctor or doctor's nurse if it has them worried, so they can ease your mind.