Can I use this?

I just bought this for a yeast infection and the back says
Do not use if you have never had a vaginal yeast infection diagnosed by a doctor
Why is that? This is my first yeast infection and I'm 90% sure what I have is a yeast infection. I have a doctors appointment scheduled but not until this coming Tuesday and I don't know if I can handle chillin with this thing until then. Is it okay to use anyway? I'm desperate 😩 I would've purchased the one with the pill applicator but this was all I could afford right now