Monistat 3

Ashley
So I just bought Monistat 3 day treatment 
Because I just found out I have a yeast infection
But I was reading the directions and it says I shouldn't use it if I've never had a yeast infection diagnosed by a doctor. 
And I have all the symptoms for a yeast infection so I'm pretty positive I have it but now Im worried that I could be wrong.
I just want to know if I should just use it or should I go talk to my doctor.