craftgrrl | a question about sewing machines...

Hey everyone, I have a question.
I've been breaking a lot of needles lately. i'm not too familiar yet with needle size/number vs weight yet..i do use jean needles when sewing through jeans (heh) or heavier upholstry fabric...
but when sewing through double/triple layers of fleece or a thicker cotton weave..I am breaking needles..or bending them severely..and they bend forward towards me..it is strange (to me)

so my question, am i using needles that are too light? or could it be a machine issue? i find it happens most when i am going through a couple layers (like a rolled hem for example) and i usually just go through those parts slowly, turning the needle by hand..but it does happen on straight-away parts of a seam...and it is really frustrating!

any insights? could this be an issue of timing or do i just need to learn the subtleties of needle size a little better?

sorry i prattled on for so long about it ^_^

xposted to a few other places
i'm dyin here.. ;P