Yeast infection

Rebecca • 17. Getting ready to be on my own. Trying to live the best life I can while battling depression.
Can someone explain to me what a yeast infection feels like? I think i have had one before, so I used the medicine just incase. It helped. By now, 7 months later (same time of month too) and I have the same feeling back. Both feelings happened after sex. I'm just wondering if it is a yeast infection or maybe something else.