Pregnancy test was negative then turned positive?

“I took a test the other morning, i looked at it, it was negative. I looked at it again after work after it was in my car for hours and it was positive, the brand has 2 windows one for the evap line and one for the positive line. I took two more (different brand) and they are negative. one that night, and one the next morning, and they were both negative. but the positive line, was CLEARLY positive, no doubt about it, not faint at all. I’m not at a stand still about what is going on. can someone PLEASE tell me any of the reasons why i may have gotten a false positive or why the other ones are negative. I am four days past my period now. also i know about not looking at the test 10 minutes after i took it but the thing is that i only glanced at it and was like “phew ” and threw it in a bag in my car to throw away, it could have changed to positive within the ten minutes and now im kicking myself in the ***. could the other ones be negative because they were a different brand, am i pregnant, is it a chemical pregnancy? i am on no medications whats-so-ever that could cause a false positive. i have heard that pregnant or not you can always test a negative but almost no one tests a positive when they actually aren’t pregnant. needing help… boobs sore, initial “period” bloat is gone no signs of period, going to the doctor ASAP”

A: When taking a pregnancy test, it is very important to read the instructions before use. Most tests require waiting a specific amount of time before looking at the results. The negative test result was more than likely accurate. If you let the test set for a longer period of time, the result will not be accurate. If still concerned about pregnancy, we recommend scheduling an appointment at Family Planning for a pregnancy test