I work in the deli area or the fresh produce at Walmart. I had to call in to work for a week due to me being sick with a nasty cough. At this time I had no idea what it was. I was congestive through my nose and throat. I was barely able to talk. When I called in to work the day before my doctors appointment one of my employee told me that my manager was gonna fire me due to missing so many days for being sick. My doctor gave me a doctor's note for three days off. I had called one of my employee to see how things were and he told me that once I go back that's when they are going to fire me.
As somebody who has actually worked at Walmart in the past (5~ years while I was in high school and college) I can confidently say that this is absolutely part of Walmart's modus operandi.
Their absence policy is pretty strict. It varies slightly state-to-state, but I believe the policy at my store back in the day was 6 days in 6 months and that was a hard cap. At 4 you would receive warnings, at 6 you were usually fired within a few days of returning to work.
However, to my understanding, different stores enforce this limit differently. Sometime the hardest working employees were often given a little leeway and if it was their first offense.
I don't want to sound all doom and gloom, but if this isn't your first time taking extended periods of time off, you might be in trouble here. Regardless, don't put too much stock into what your coworker is saying - they probably don't know any more than you do.
If you're getting jittery and want to talk to somebody about the policies, you can always call and talk to your direct manager (talk to your associate manager; if they can't answer then speak to your co-manager).
You have a Doctors cert for 3 days but took a week off and you don't know what is actually wrong with you despite going to a Doctor.
If it's at will they can fire you any time they want. There is no need to wait until you return.
So more than likely it's just noise. You may get a bit of a hard time, but if they were to fire you they could have already. The other thing is they might not have made up their mind, at the moment your story looks a bit dodgy, they may want a fuller explanation before deciding on whether to terminate your employment or not.
The last possibility is they have a policy that an employee has a certain timeframe to get a doctors cert within if they're sick. In which case you may indeed be in pretty big danger of being sacked. If such a policy exists you should have learnt it at onboarding or been told when you rang in sick.
When I called in to work the day before my doctors appointment one of my employee told me that my manager was gonna fire me due to missing so many days for being sick.
I could be wrong, but I'm reading between the lines here. To me, this doesn't sound like he's saying you're going to be fired because you've missed a couple of days this time around - he makes it seem like you have a history of often calling in sick, and as such he needs to find someone more reliable as an employee.
Can he fire you for this? In an at will state, sure. Will he? No-one can say. If you have a history / reputation for being unreliable, then it might be that this was the last straw. Or he may have calmed down by the time you go back, and decide to give you another go. Or the employee could be grossly exaggerating / lying. (Picking between one of the above is just guesswork for us at this point, though.)
Can they fire me due to being sick?
If you are in an at will state, and not part of a union, they can indeed fire you for this reason or for no reason at all.
But if they will fire you - that's a different question.
If you aren't habitually taking absences, and you are otherwise a good worker, then it's extremely unlikely they will fire you. Good workers are hard to find - particularly in these days of low unemployment.
The only way you'll know for sure is to see what happens when you report back to work.