Irregular periods

Cristina
So I'm not sure if I'm back (out of The blue) to having irregular periods... My last period was in January and all my pregnancy tests are coming back negative... 
​My question is, how can I keep the app from changing my period date to the following week? Is there a way to erase it for the month and just input when it comes?
​For example, my period was due on the weekend of Feb 14... And I went to erase it and it just forwarded it to last Friday and it never came, so I edited it again (deleted) and it forwarded it to this weekend.