Check your oil in morning before starting engine so the accurate level you can get when engine is not running and all oil make it to bottom overnight or at least leave your car for 2 - 3 hours to see correct oil level.
As i said in my previous post, it seems the same case i witnessed in my hijet and it was tappet issue. Check if your car jerks a little when you drive right after starting for the first time in morning, you will feel like car is braking a little while you start driving slowly.
My suggestion will be to go to a good mechanic and ask him to check your car's engine compression with gauge and check for the values, good compressions will be between 150 - 200psi also check your car's manual or google for your engine default compression values.
Thanks.