Okay at aproximately 8:00 a.m. I took dayquil for this cough ive benn having,  At 4:30 i noticed there was no more dayquil so i took tylenol.  After that i read that you arent supposed to tynenol with another product containg  acetaminophen.  Is this because it causes liver damge or because its like life threating.  Should I contact my doctor or what????

If you took the suggested dose of both products, most likely you have not ingested enough acetaminophen to make yourself sick. However, this chemical is especially dangerous to your liver when taken in high doses. You most certainly may call your doctor if you are feeling worried, but be sure and avoid alcohol for at least 8 hours. The combined effects of alcohol and acetaminophen are very bad for your liver enzymes.

look at the dayquil botle if it says u can take it every four hours 6 hours whatever and thats when u took the tylonol ur ok but if the dayquil was more then 8 hours  call ur dr

I would call him to be on the safe side of things, or call into A&E