Precisely 30 days since my stupidly unprotected intercourse. Heavy crimson flow arrived 19 days ago, right on schedule. I've had a bloated, distended abdomen for a week. Gassy. Queasy. I struggle to catch my breath at times.
Thanks for any insight.

Since your period appeared to be the norm for you, your symptoms are unlikely due to pregnancy. However, you can certainly try a pregnancy test to ease your mind.

Some women will have bleeding in early pregnancy that is mistakenly thought to be a period. Often it will be different in some way from what they normally expect, such as arriving a bit early, or slightly lighter flow.

If you test and have a negative result, but continue to feel unwell, see your doctor. They may check for pregnancy as well.

The "signs" can be many thing. And a period, should mean you are not.

When is your net period due?