The Blades have not won any of their seven matches under Adams since he replaced Gary Speed at the end of December and are four points adrift of safety after sliding into the bottom three.
Adams said: "Obviously it's worrying, it was a difficult job when I took it on and it is even more so now."
The former Port Vale boss said: "Can it get much worse? I hope not. But you've got to be fearful that it could.
"Everyone at this club has got to take collective responsibility for the situation we are in.
"The players, the staff, previous managers and myself, even though I've only been here for less than two months. There's nothing to be gained from hiding that fact.
"I will have to go away and question myself and I'm sure, if I have missed a trick, someone will let me know."