When to test?

Haven

So I started birth control the day my period started but me and my fiancé had been having sex for at least a week before that. I didn’t know it takes at least 3 cycles for the birth control to work 🤦🏻‍♀️ I’ve never got taken bc before and the dr did little to explain hence my ignorance. I already have an almost 3 year old little girl and I’m kind of freaking out. I’ve been extremely tired lately and nauseous and just downright feeling weird. My AF isn’t due again til August 12th but I’m anxious to know if I’m pregnant or not. When would be okay to test?? I bought some dollar tree tests but should I get better tests?