The holiday season is around the corner, and you're probably looking forward to in-person celebrations with loved ones.

And though you might not want to think about it, testing positive for Covid just before one of those gatherings could put a real damper on your holidays.

So, if that happens, what should you do? There's a short answer and a long answer, experts say.

The short answer is simple: Don't go, even if you don't feel sick at all.

"People might feel well enough to participate and think that maybe the rules don't apply to them," Dr. Dean Blumberg, chief of the division of pediatric infectious diseases at UC Davis Health, tells CNBC Make It. "But you have to realize that if you're not following guidance from the CDC, you will be putting your family and friends at risk of infection."

The long answer is a little more complex, because your next steps could affect a lot of people in your family or social circle.

A recent survey by travel site The Vacationer found that more than 112 million, or 43%, of American adults plan on traveling to a holiday gathering or vacation destination for Thanksgiving this year, slightly higher than the 109 million that said the same last year.

But health officials still warn of a winter Covid surge that could wreak havoc, just like last year's winter wave of omicron cases.

Here's a guide for what to do if you test positive for Covid right before a holiday gathering with loved ones:

Isolate appropriately

If you test positive for Covid before an event — whether it's a day or a week beforehand — experts say to follow the Center for Disease Control and Prevention's newest isolation guidelines:

• Most people should isolate for at least five days, regardless of symptoms, because that's when you're most able to spread the virus to others. If you're elderly or immunocompromised, isolate for 10 days.
• If you don't have any symptoms on the sixth day, or if your symptoms are improving and you haven't had a fever for 24 hours, you can exit isolation. If your symptoms involve shortness of breath or difficulty breathing, you should isolate for a full 10 days regardless of any improvement.
• Once you've exited isolation, wear a high-quality mask around other people through day 10, or until you've tested negative on two rapid Covid tests 48 hours apart.
• No matter what, avoid people at high risk of severe Covid until at least day 11. That includes people who are elderly, immunocompromised or have underlying medical conditions, according to the CDC.

If you end isolation after five days, you could potentially attend a gathering that occurs on day six or beyond if you wear a high-quality mask around others, says Dr. Timothy Brewer, a medicine and epidemiology professor at UCLA Health.

But he says it all depends on who exactly you'd see at the gathering: If there's anyone at high-risk, don't even think about going. If not, you should still make sure everyone else is comfortable with your presence.

"It's going to depend on each individual circumstance. I'm not going to see my 87-year-old mother-in-law if I test positive," he says. "But if it were my 34-year-old son and kids in Indiana, I might still go if it's been at least those five days and I wear a mask." 

If this forces you to miss a holiday gathering, don't despair: You can still find ways to participate, Blumberg says. You could join the party on a phone or video call, or try to schedule another get-together once you've tested negative.

Alert your social circle

A positive Covid test means alerting the people you've seen over the prior few days, so they can monitor and test themselves just in case. It means alerting the loved ones you were supposed to see at your holiday gathering, too.

That can be a "really tricky" conversation, Blumberg says: People might judge you as being irresponsible, or accuse you of ruining their plans by not attending. They might even insist you attend anyway, saying they're at low risk of severe Covid, up-to-date on their vaccines or simply unbothered by the risk.

In response, you can remind them that breakthrough infections are "very real," and so is the potential to spread the virus to high-risk loved ones, Blumberg says.

You can, of course, lower your risk of getting Covid right before a holiday gathering, he adds: Get the new omicron-specific Covid booster if you're eligible, and mask up in crowded situations ahead of time.

If you haven't already, you can also get your flu shot for similar preventative reasons.

"Get both, so that there's no question of you being healthy and maximizing your protection," Blumberg says.

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