heating problems!!!! help!

so i feel like i always post about my heating issues (ok it was only once before, but whatever). anyway........so i have oil, and my heater is going on....but the thermostat is set to 75 and it's only 65 degrees in my house!!! does anyone have any idea what this could be or any ideas for what i can do??? in some ways it was BETTER when we were out of oil b/c at least we KNEW what the problem was!!!! does anyone know anyone in this business or just has anyone had similar problems???
PLEASE HELP!!!

oh no...... did you call your oil company? do you have one? keep raising it, i bet your thermostat is broken and not reading properly