Can I be laid off if the company Dr tells me not to return to work?

Very difficult to give you much guidance without additional information. I'll assume the condition preventing you from working is not a work injury.  Your employer can reasonably expect you to be physically capable of performing your job duties and does not have to hold your job for you indefinitely while you are unable to do so. If your employer is covered by the Family Medical Leave Act (50 or more employees) and you've worked there for 12 months, you may be eligible to take leave under FMLA.  You should ask your employer about that.  If you are able to perform your job with reasonable accommodations, you should ask your employer about that and you might have protections under the Americans with Disabiltiies Act.    Best bet -- call an attorney with experience in employment law, discuss the facts of your situation and get some specific advice.