President Trump on Friday evening tweeted a pre-recorded video message thanking Americans for their support as he battles COVID-19, the first time he has been heard from since sharing news of his diagnosis. "I want to thank everybody for the tremendous support," Trump says in the 18-second clip, tweeted moments after he arrived at Walter Reed National Military Medical Center. "I think I’m doing very well but we're going to make sure that things work out," he added. "The first lady is doing very well. So thank you very much. I appreciate it. I will never forget it." The president's...