My OG was wy low (1.031 should have been 1.044). Four days later it was up to 1.034
Since the change from 1.031 to 1.034 is impossible without making additions, the first was likely incorrect. If you are brewing extract then the OG can be mathematically calculated pretty accurately, so probably the 1.044 is correct for an OG.
As others have suggested check your hydrometer. Also check your technique: along with adjusting for temperature swirl the hydrometer, make sure it isn't touching the sides, clear away any foam so it's easier to read, etc.
You can test your technique by measuring the same sample four or five times. Measure, remove the hydrometer, replace, measure again. Should always be the exact reading.
With the beer so far above the expected finish I'd be worried about bottling unless I got the same reading several days in a row -- and I'd probably still be worried. But that may just be me.