Do you listen to Car Talk on NPR?  You should!

Change the oil and fill with the correct amount.  Then get your rod and
make a temporary dip stick.  Or, you can just add a half quart every 200
miles until the new stick comes.

If you know how long ago you added a half quart, just go from that
benchmark and wait for the stick to arrive.

You must have a serious case of oil leprosy for the end of the dipstick
to fall off.

Stuart