If you have been sexually active over the last month...
And in particular if you haven't been using condoms...
You really should go to the doctor.

Because there are things that can mimic yeast infections but that need a different kind of treatment.

And it is important to get those ruled out. I think it can be hard to tell what you have even if you are used to having yeast infections on occasion.

Personally... I've used the creams (which are ok. have to use them if you happen to have your period). You need to apply them for about a week though. There are also pessaries which are a little like putting in a tampon. If you get the latter... My advice would be to ask specifically for one that only needs to be applied once. Some of them need multiple applications, but there is a kind that only needs one application.

I've never brought anything OTC for it. I've always gone to the doctor. Once... It wasn't a yeast infection it was some other kind of bacterial infection (not sex related) but still... I thought it was a yeast infection and it wasn't. The treatment for it was different. I think you can get OTC stuff for thrush now. I remember there was quite a bit of controversy over that one in NZ because the doctors were concerned that women would assume they had a yeast infection and try and treat it OTC when they could have something a bit more serious and / or something that needs a different kind of prescription.