The Portuguese coach has been unable to improve the Red Devils' fortunes since taking charge in November and knows that his position as manager is at risk if results don't get better over the rest of the season.
Speaking before United's FA Cup tie against Leicester on Friday (07.02.25), Amorim said: "We are fighting for our jobs until the summer. I'm just focusing on these games.
"I knew when I chose this profession that you have the risk of the results and I already knew when I came here.
"I looked at the schedule, I looked at the team and I understood that my decision of changing everything, taking these hard decisions in the middle of the season - without new signings - is a danger for a coach.
"But since day one, with good results or bad results, I have a clear idea what I want to do and I take these risks because, in the end, I think it is going to pay off.
"But I'm not naive; I already said many times that this is a sport of results and we are in a difficult situation."
Amorim is also determined to move on from the Marcus Rashford saga that dominated the club's January transfer window following the forward's loan switch to Aston Villa.
The manager said: "Thankfully about Marcus, he is in Birmingham now, with Unai [Emery] so you can take the questions for these months to another coach.
"We are focused just on our players at the moment.
"I couldn't put Marcus to see the way you're supposed to play football and to train the way I see it.
"And sometimes you have one player that is really good with one coach, and the same player with another coach is different.
"I just wish the best to Rashford and to Unai Emery, and they can connect because he's a very good player."