[Kindred]

If you used a condom, it's highly unlikely you're pregnant. Although they're not always effective, they are pretty safe.

Yes, it's likely this is caused by stress. If you still don't get your period soon, take a test (or if you're really worried). But I would say you'll be fine. Periods can be regular and then turn completely irregular, or vice versa, and stress is one of the things to influence them.