I'm late

Brittany
swears that I'm pregnant, but ever test says negative 😪 I just stopped my BC last month and I'm assuming that threw my body off.... But it's weird because I was only on the BC for 3 months and when I first started it... I never got thrown off. I still had normal periods and everything. I really want to be preggers. Now the app says I'm supposedly in my fertile window but I have no idea because I never had my period. Would I still be fertile at the time I was supposed to be? I'm so confused.