Had a time slip with physical consequences

I have a busted elbow I've been taking Tylenol for. It's killing me. Been taking one Tylenol every 4 hours so I can take the max without exceeding the recommended dose. Adhere to it like a train schedule. Sunday I was composing a rather long, angry email to someone and my arm started making me nuts. Looked at the clock and it said 3:55. Great, 4 was okay for the next round. Seemed like a fast 4 hours so I checked the time on my phone to make sure the clock wasn't off. It said 3:55 - so I took the Tylenol.

At this point I had to go get dog food before Petco closed so I saved the preposterously long email I'd spent the last hour typing (it auto-saves anyway, but I saved again just to be sure) and left. I went to Petco, Costco and Ralphs. I lugged all my shit inside and my arm started bothering me again - like I'd been hours without taking anything. Checked the clock to see how much longer I had 'til the next round of acetaminophen and it said 3:50. WTF? Power must've gone out. Check my phone. 3:50. So that's weird. Chalked it up to a brain fart.

Put the shit away, feed the dog and go back to my email. The email is all gone except for the first two sentences. Like I'd never written any of it. So now I'm a little freaked. If I were prone to flights of fancy there'd enough evidence there to make me believe that I'd just slipped back in time by about an hour.

Of course that's crazy so I let it go.

I noticed it'd happened again yesterday morning at exactly 11:38. The only reason I'm watching the clock that closely is because I'm taking the Tylenol. And I'm not blacking out because the slips go backwards. Took the Tylenol at 11:30am, checked phone and wall clock because of what happened Sunday - got a little work done, watched a TiVo'd episode of Family Guy and American Dad, arm starts bothering me, check the clock; 11:38.

Now I'm a little concerned. Am I going nuts? If so, how am I actually getting shit done during the period of missing time? I'd write it off as mental but I'm accomplishing things in the weird extra hour (it's more like 50 minutes). I have RedBull and dog food I bought during one episode and I lost an email I'd written during the other. What the fuck is going on?