Usually, if there is even a faint line, it's positive. Your best bet right now is to either wait a few days and retest, or go get a blood test. I know at the hospitals here you don't have to have a doctors order to go get a pregnancy test, but if you don't have an order, you have to pay for the test. It's usually only like $13 or something. So call the hospital in your area and see if they will do it.
Just a note to let you know about HPT's: The ones they use that the doctors are the same as the ones you can buy in the store. More expensive doesn't always mean better, and dollar store ones work just as well as the more expensive ones. Also, sometimes waiting a few days will help insure a correct result. If you think it may be positive, but can't tell for sure, wait a few days then retest. Usually by then your HCG levels are high enough that it will show for sure. More then likely last time, your levels were higher, so it picked it up faster. Good luck!! I hope you get the results you want!!!!