meter inaccuracy

Last night before dinner I checked my blood sugar and it was 170. I was surprised because it was much higher than I expected, so I tested again using the same meter...... and it was 124. I was shocked.

This morning I checked my blood sugar with my regular Aviva meter and it was 103. Then, using the same drop of blood, I also checked using my one touch meter, and it was...... 128. What? I checked again using both meters and now it was 112 and 106. I am very surprised by how inconsistent these meters seem to be, even with the same meter and same drop of blood. Is this normal? How am I suposed to make decisions about insulin when I don't trust the meter? How do other people deal with this problem?