I did not have any oil shown on my dipstick

Hello,

If there is no leak, then it is likely the engine is burning oil.
Usually when this happens you will get blueish smoke out of the tailpipes.

An engine can burn oil due to several reasons. It could be due to broken piston rings, worn valve stem seals, plug crankcase ventilation, too much clearance between the piston and engine block.
Really anytime that oil enters the combustion chambers it will burn and produce blue smoke.

https://www.2carpros.com/articles/blue-smoke-from-engines-exhaust

The best course of action would be to look at each individual component and take necessary action.

One way to check if there is oil in the combustion chamber is to remove the spark plug and inspect for oil fouling. There will be wet black deposits on the spark plug insulator.

Repairing the oil burning can be labor intensive, depending on the exact reason for the issue. For example, a broken piston ring will require the tear down of the engine.

Please let me know if you have any questions.
Thank you.