No point in stressing, it will only make matters worse.
Most people recover fully from shingles, and if you started the antiviral medication within 72 hours of the full rash appearing, that improves your odds.
It is difficult to diagnose shingles before the full rash appears and indeed, pain that precedes the rash is often misdiagnosed, since it is also nerve pain. In fact when I had shingles about 10 years ago, I had what was thought to be pain from a back problem for about a week before hand. Only when the characteristic rash appeared was it apparent what was going on.