I hope this does not sound stupid, but I was wanting to ask experts
What would most likely be the cause of loose insulation, blowing
In the ducts, and clogging the vents. I have been in the attic looking
Around, but did really see anything out of the ordinary. It has started
In the last couple of months.
Thanks for the help, Rod.;)

Most likely you have a leak in a duct on the low pressure, return, side somewhere. Attics are not fun places, but you are going to have to track it down. Look for places where the insulation is piled up on a joint, or seems to be thin. Just keep looking around and feeling for drafts with the system running. Once you find the leak, it may be a proper place to use duct tape as the permanent solution.

Check your filters too. They may have clogged and collapsed from it. Otherwise, they should catch it.

Thanks for the info, that helps me know where to start.

Another possibility in this situation is the type of ductwork u have in your house a lot of older systems have what's called ductboard which is actually made of fiberglass over time this breaks down and could cause the exact problem you are having so in addition to looking for leaks in your ductwork before doing so determine whether u have metal or ductboard for your trunk lines as this may be a cause of your problem as well