Klonopin (clonazepam) is a schedule IV controlled substance and whether or not you can fill it depends on a few factors. In regard to when your actual prescription expires, Pennsylvania law stipulates the following:
"Prescriptions for Schedule II controlled substances may not be filled more than 6 months from the date of the prescription. Prescriptions for Schedule II controlled substances may not be refilled. A controlled substance in Schedule III, IV or V may not be filled or refilled more than five times in the 6-month period from the date of the prescription."
As your prescription was written on Jan 16, you are well within the legally allowable time frame to fill it. However, whether or not you can get it filled will depend on the day supply of your prior prescription. If you still (or should still) have tablets remaining on your prior prescription, you may be denied the fill. For example, if you last prescription was for 30 days, your new prescription would be considered too early to fill.
If there are extenuating circumstances (e.g. your forgot your tablets at home), you may need your doctor to phone the pharmacy directly to explain the situation.