Calm down buddy get to know the detector before hasting out with those "hotter" programs take it easy in the beginning.
Begin with using coin and jewelry and push up AC sensitivity and PreAmp gain. When using the big coil try using
15Khz only to get those smaller targets better.(or 3Khz for coins)
Here is how to set the MD "hot" with AC sens and Preamp

After ground/air balancing and selecting program)
1. Set Preamp to 3 and AC to 74
Is the detector stable? (Keep it at waist level when doing this)
2. If Yes increase AC with 2 until unstable then lower with 1 until he is stable.
If No decrease with one until he is....If your below 69 (approx) try using Correlate frequency.
Correlate should be stable enough for you to up AC quite a bit.
3. When he is stable go hunting.
Note! When pushing up AC sens and Preamp don't forget to push up DC sens to! (DC is for pinpoint)
You can try this basic way to increase depth.
Look into the book "Digging Deeper With The DFX" by Jeff Foster.
Read the manual, even the white's website has one you can download to read today.[Hint]