You might want to change your oil change interval to something shorter just to make sure you catch things before they get this low. It's odd that your dipstick isn't reading right - since it's actually measuring the level in the oil pan, it makes me wonder if there's some big blob of "crap" in the pan or something that's causing the level to not register properly. Have you ever peeled it off and taken a look? Make sure to get a gasket if you're so inclined.

-- John