Home pregnancy tests are 97% accurate, take another test to be sure. Home pregnancy tests test for a hormone called Human Chorionic Gonadotropin (hCG). The earliest you can take a pregnancy test would be 14 days from actual conception.

Reasons for a false positive include a chemical pregnancy (its an early miscarraige, half of all first pregnancies end this way, but your body still has the hormone). Missed reaction time, seeing the test too late or too early. Infertility treatments, or medicines with hCG in them. If you're using a pregnancy test with lines, sometimes it leaves a faint evaporation line, as the urine crosses the test. This faint very light grey evaporation line in the test area is often interpretted as a positive result.

Crohn's disease can cause diarrhea, but many other things, including poor diet, too much fiber, food poisoning, and bad reactions to foods, can cause diarrhea. Crohn's affects around 400,000-600,000 people in North America, so its relatively rare. In severe cases, an individual may have more than 20 bowel movements per day and may need to awaken at night to defecate. And depending on what part of the intestine is affected, will depend on your symptoms. I highly doubt with your only symptom being diarrhea that you have Crohn's disease, talk to your doctor about your gastrointestinal issues though, if you're concerned about it. But even if you did have Crohn's disease, it would not affect a pregnancy test.