Record yourself.
When you're by your lonesome, you have no reason to be nervous. You can let your brain flow freely -- so record yourself now! Your English is going to be at its best. Find a BOOK on tape or a clip online that you can mimic. Does your English sound the same?
Or record yourself reading from a BOOK. You'll be able to actually hear yourself (which we surprisingly have trouble with in real time) and be able to pinpoint the quirks in your English and where you slow down and have trouble. Then rerecord it and see how you've improved!