Do I trust what the ClearBlue Easy Monitor says?

This is my second month using it. The first month it gave me high fertility on days 9-12 and then peak on 13&14. This month it gave me high on days 6-8 and then peak on 9 & 10. I did have slight cramping on day 10 so I thought that may be ovulation cramps but my cycle is always only 28-29 days long...how could my peak and high fertility days be off so much? Is it maybe because the last month was the first month using it...that this month is more accurate? Can ovulation occur as early as day 10? We bd'd every high and peak day, only not on the high day following peak. I have had two miscarriages now and am 37 yrs old, trying for 2.5 years now. I want to trust in something to help!