Six days ago, I injured myself doing a deadlift in the gym. I've told pretty much everyone about my stupidity, so I might as well share it here - it might prevent you from doing something similar.
I've been following the weightlifting protocol 5/3/1 where you work to pretty tight progressive weights over the course of the session and the weeks. I was only using it for a couple of lifts, including my deadlift.
So, there I was last Sunday morning... I did a 5 rep set x 30kg, 3 x 36kg, 3 x 41kg, 3 x 51kg and the last set was as many reps as possible at 58.5kg. I did 4 good reps, and went for a 5th...
Now... something happened between that 4th and 5th rep, but I don't quite know what. I lost concentration, I forgot how heavy the bar was, I didn't push through my feet but pulled from my arms... One or all of these happened, and the top of my left glute went ping. I heard it.
I dropped the weight, said 'ow' very loudly, decided to give up the rep and even tried to bend down to unload the bar. Yeah, that wasn't going to happen. I shuffled into the gym office and promptly fainted on my colleague.
I was completely laid up for two days, and in pain ever since - a sharp pain when I move the wrong way, and a dull ache at all other times. Standing still is not easy, and sitting down on a proper chair is impossible - I have to slouch back propped with cushions and my feet up.
I've also completely finished a box of chocolates, snacked at all the wrong times, and I can feel myself getting weaker and less fit with every passing minute. But I am using this time to ditch 5/3/1 and go back to my own system, which was actually working very well.
To finish, the moral of this story - the thing you should remember whether you're lifting 20kg or 200kg - is respect the weight, don't lose concentration and try really, really hard never to faint in front of the people you work with!