The timer variable in VB keeps track of how many seconds have elapsed since midnight which is why you are having this problem. I would reccomend using the VB "Now" function as that keeps the full date. You can figure out differences in time using a VB function called DateDiff. It works like this:
DiffInMinutes = DateDiff("N", Now, LastResponseTime)
DiffInSeconds = DateDiff("S", Now, LastResponseTime)
DiffInHours = DateDiff("H", Now, LastResponseTime)
DiffInDays = DateDiff("D", Now, LastResponseTime)
LastResponseTime = Now