So sick of playing bad cop to my family

I'd love to know if anyone else is constantly the bad guy in their family. I have so little joy or levity in my life when I'm at home. I have no idea how to shut myself/my instincts off when dealing with my partner and youngest daughter (18). They only see me mad and irritated but don't see that it's because of THEIR choices.

Two examples from last night - I realized that my partner did not know that Tylenol was the same thing as acetaminophen, and was taking both Tylenol AND NyQuil at the same time for several days, I freaked out, but he just shot back at me "How am I supposed to know? I'm not a pharmacist! FINE, according to you I shouldn't ever take medicine again!" (This is how it always goes with him, taking my criticism and blowing it up to hyperbole.) Should I not have mentioned the double dosing of Tylenol to him at all?

My 18 year old had to get up early this morning to work, so she asked me to tell her to put her phone away and go to bed at 1am. But she kept saying "I will! Later! You're so pushy!" This went on until 1:45am. Excuse me, ma'am, you asked ME to be your human alarm clock!

Any advice? I seem to be simply unable to step away and let them make bad decisions on their own. I don't know how other people do that, I truly cannot. I'd just be lying in bed with my fists clenched. Please help.