Hide bump at work

I am only 4 weeks at this point and wanted advice on hiding the bump until you're ready to announce. I don't yet have one, but I'm not skinny and last time bloat started looking like a bump as early as 6/7 weeks. I miscarried my last and would like to keep it a secret until we are farther along.

I live in AZ, and it's in the 70s for winter. I can get away with an oversized hoodie at night with friends, but how do you hide a bump at work with warm weather? Thanks for your help!