Two questions get muddled here. Whether it is good for you, and whether it is fair on the rest of my room. The second matters more and gets asked less.
The one that matters
If you are contagious, stay home.
A shared room, shared air, close quarters and a lot of breathing. There is no version of this where bringing something in is a neutral act, and the people most affected will be the ones with the least to spare.
Everybody knows this and people still turn up, usually because they have paid or they do not want to break a streak. Neither is a good enough reason, and I would always rather you told me.
If it is genuinely just the tail end
The rough guide people use is whether it is above or below the neck. A blocked nose and no fever, past the infectious few days, tends to be fine. Chest, fever, aching, anything systemic, is not.
Add tiredness to that. A body fighting something has less to give and less coordination to spare, and the second one is how people get hurt doing something ordinary.
What to do instead
Something at home, quietly, at a fraction of the effort. Slow movement and long exhales, nothing at the edge of anything, twenty minutes.
That keeps the habit alive, which is the actual thing at risk when you are ill for a week, and it exposes nobody.
Coming back afterwards
Lighter than you think for the first session. Endurance goes first and comes back last, and people consistently misjudge this and have a miserable class that puts them off for a fortnight.
One easy class, then reassess. There is no rush and nothing has been lost.
In short
Below the neck and past the worst, use your judgement. Anything else, stay home and message me rather than just not appearing.