I was happily flying on a Lowrance Airmap GPS when a "position lost" message appeared on the screen. I was flying along a mountain range looking for a particular mountain pass in limited vis. Kept on the same course waiting for the GPS to "rediscover" it's position but it didn't!!!!!!! Because restricted airspace was around me, I did a 121.5 call and was vectored to an airport by ATC.
I learned some lessons that day: 1. Never rely solely upon GPS navigation, use VOR's or VFR navigation in future as secondary back up! 2. When the current position is "lost" note time and airspeed for a rough calculation on approximate position later - at 120kts., 15 minutes here or there is a lot of distance! As it was, I had been lost longer than I had guessed and my position was actually over the map fold so looking for my position on the VFR chart was futile anyway because I simply wasn't even close to where I had estimated to be.
Don't rely on GPS, it simply isn't infallable.