I should have added, there are many natural anti-fungals, combined with dietary changes such as avoiding sugar, if it is a yeast infection that don't kill off beneficial flora. It's best to try these first before turning to pharmaceuticals, which should only be used if necessary. The overuse of antibiotics of all kinds in allopathic medicine is now almost universally acknowledged to have been a big mistake, particularly in simple situations such as a first yeast infection, mild ear and sinus infections, viral infections that won't respond to antibiotics anyway, and in animal feed.
Using monostat if you don't have a yeast infection will just kill off your beneficial bacteria -- it'll do that if you do have a yeast infection. That will just lead to more chronic problems if those beneficial bacteria aren't successfully replenished. It's a good idea to see someone for a diagnosis before you go about treating something.
Depends on the source. If your partner does not use condoms, the fishy smell is normal. You can solve that by using condoms. If its a fungus, try gentle baths with diluted apple cider vinegar.
It could be Bacterial vaginosis or a Yeast infection Buy MONISTAT.
If that doesn't help then see your OB/GYN.