Period .... No period ! Please help !!

So I was on the birthday control shot (Depo) for 5 years ... I stopped getting them oct. 2017 . I didn’t start having periods again until April 2018 .. I’ve had one every month since then .. but my August period was a few days early .. and my eve app says my September period should’ve started August 31st .. and it still hasn’t started .. could it be that it’s just irregular .. or ? I took a pregnancy test and it said negative ! I’m lost .. should I go to the health department and get a professional pregnancy test ? Orrr ?? HELP !!!