Those symptoms could certainly indicate pregnancy, especially since it sounds like you're actively trying to conceive. When I was pregnant with my first daughter I thought that I was experiencing cold and flu symptoms but it turns out it was early pregnancy signs.
If I were you I would wait to take a test for one more day. Begin testing the morning of March 13 and if the test is negative, wait to test again until the morning of March 15.
Something to keep in mind is that although ovulation apps and calendars are really helpful, unless you're temping and charting, or confirming ovulation with an OPK, it can be difficult to know for sure when or if you've ovulated.