So I'm going to answer very literally because, well, look where we are: a complaint is simply a type of statement, and it's a necessary part of healthy communication.

If you say you're tired, and you mean it as something you wish weren't true, then that's a kind of complaint.

But also, I think our society has maligned the concept of a complaint and loaded it with baggage that it doesn't deserve. I think "stop complaining" is weaponised by people in power to prevent having to address people's needs, because "my needs aren't met" is a kind of complaint. It just also happens to be absolutely necessary to complain of something in order to fix the problem. This negative attitude towards complaint gets internalised by everyone to some degree.

So your friend might have some of these attitudes without understanding that they are problematic.

Also, you might be tired a lot, particularly of going out, because having to mask is a pretty big burden. If you can explain this to your friend and they can accept it, it might help you develop some kind of shorthand for the issue so you don't feel like you have to justify it in their terms from first principles every time. Maybe you can get some help from them, maybe they can find ways to reduce the burden, like maybe they can interact with cashiers for you, or something like that, or they can simply adjust their expectations of how much or how often you want to spend time out of the house.