How to avoid going into the office

I’ve been working from home since the pandemic started and I’m unvaccinated (personal choice). WFH is continuing and currently it’s optional to go in the office, but my manager has suggested me and my team go in for one day next week to see each other face to face and go for lunch. I’ve not announced my pregnancy at work yet so just looking for excuses to get out of this? 😂 I am really worried about mingling with colleagues in an office with no fresh air for 8 hours? And I’m still feeling sick around certain food so I don’t want to go for a lunch.