Is it normal to have brown spotting or discharge before your period

Hey guys. I'm totally freaking out. For the last 2 or 3 periods, they have started out brown. Only spotting enough to wear a pantyliner. I usually start bright red or a little pink so I'm a little worried. I've goggled and it's saying I could have low estrogen which would of course result in me not being able to conceive. It could also be a sign of an infection or STD which I highly doubt. I've only had sex once in the past few months and it was with a condom. I'm not itching and it doesn't have an odor. Is it normal for you guys to start off with brown spotting or discharge? If not, should I be worried about infertility? Please help