What has been described as a Hail Mary effort to repeal and replace Obamacare is currently underway in Congress with a vote expected in the next week.
The Graham-Cassidy bill would allow insurers to discriminate against those with pre-existing conditions and could lead to millions losing their coverage.
On Wednesday 20 September, Donald Trump tweeted his support for the bill, saying: "I hope Republican Senators will vote for Graham-Cassidy and fulfil their promise to Repeal & Replace ObamaCare. Money direct to States!"
But it has emerged that shortly before he issued that tweet, he blocked one of his opponents on Twitter who reacted angrily to the bill.
Laura Packard of Las Vegas suffers from Hodgkin's Lymphoma and accused the president of putting "America last" by saying "your latest TrumpCare bill would mean 32M Americans will lose their health insurance. What about putting them first?"
Speaking to ThinkProgress, Laura, who is suffering from an advanced level of stage 4 cancer, said: ""I didn't sleep too well because of the cancer.
"But I don't know if he just woke up on the wrong side of the bed today or what."
Asked about how being blocked by Trump makes her feel, Packard said: "I just wish that he would listen."
"He said he would come up with something that was great and was going to cover everybody, and [Republicans] keep coming up with bills that are the exact opposite. He's definitely not listening to me now."
Republicans have tried in vain to repeal and replace Obamacare for much of the past eight months to no avail.
They have until the 30 September to pass the bill before rules say any bill that comes after that will need the support of more than 51 senators, which would mean Democratic backing.