How long have you been on the dexedrine Clint? I've been on a year and a half and after an initial breaking in of about 3 months I've had little trouble. Consider also I am on rotating shifts around the clock and you can see that it causes little concern.
I must admit I started on the spansules (extended release) and never tried the short release. I find that the 6 to 9 hour duration means I can take one or two doses a day and get all-day coverage. For a day shift (7AM to 3PM) I take the first dose about 5AM and the second at 11AM when I get my second coffee break. This gives me 12 complete hours plus it lingers until I wind down later in the afternoon.
Big thing - keep the last dose as far from sleep as possible. If you aren't in a job that requires physical work and don't do exercise then it may be you are feeling a high metabolism kicking in with no release. Maybe try a long walk before sleep or going to a gym? I find that I sweat out most of the meds before sleep and that it very rarely has any left over.