The double World Champ suffered back pain and headaches following his 25G impact over the kerbs in Abu Dhabi.
But despite racing with his back taped up, Alonso put his F138 home in fifth place in Sunday's United States GP.
The Spaniard later revealed that he feeling stressed and tired but hoped to recover a bit before the season ending Brazilian GP.
"I'm tired," he old ESPNF1. "I'm tired; also I didn't have good preparation for this race physically. I was one week on the sofa, in bed with headaches.
"The race was demanding, it was not an easy race, I had to fight all the way through so physically I feel tired now. I felt stressed all weekend from all the battles etc.
"Hopefully I can feel a little bit better in Brazil, less tired, enjoy the weekend a little bit more. But there are some targets to do with the Constructors' Championship etc so it's not as if we race for fun in Brazil.
"It might seem like that from the outside - there's nothing more to fight for, you go to Brazil to race and have fun - but there's a lot of stress and a lot of pressure on these weekends for the team and we'll all try to do as well as we can."
Alonso, however, has all but ruled out Ferrari achieving second place in the Constructors' Championship after dropping more points to Mercedes on Sunday.
The Scuderia now trail the Brackley squad by 15 points with Lotus 18 points adrift in fourth place.
"We wanted to close the gap a little bit in the Constructors' Championship; that was the goal. We did not have the pace this weekend to do that and we lost a little bit of points again while Lotus got closer, so not a good weekend in terms of points.
"But there's nothing we can do at the moment, we didn't have the pace, we were too slow all weekend; we fight to be in qualifying three, we fight to be in the points on Sunday.
"So we need to do better in Brazil if we want to fight for the Constructors' Championship or that was too optimistic a goal. We need to be more realistic and know that fighting for second place in the Constructors' Championship was a dream and maybe that dream is difficult to come true."
