It is not uncommon for some individuals to experience two periods in a month. This can happen due to various reasons such as hormonal imbalances, stress, or changes in birth control methods. If you are concerned about this change in your menstrual cycle, it is recommended to consult with a healthcare professional who can provide personalized advice based on your specific situation.
As for the pregnancy test, it is possible to get a false negative result if taken too early or if the test was not performed correctly. If you still have concerns about being pregnant, it is advisable to wait at least a week after your missed period and then take another test using your first morning urine. This will help increase the accuracy of the results.
Remember that every individual's body is unique, and it's important to listen to your own instincts and seek medical advice when needed.