Just discovered mold in my basement apartment, green and white and fluffy?

I was away from home for a couple of weeks, and when I came home today I walked into a very smelly, damp feeling apartment. I've only lived here since March, but since the weather has warmed up I did notice it was very cool and damp all the time - I was kind of relieved with the cool air, didn't need to buy an air conditioner, but the dampness concerned me a bit. Anyway, after cleaning almost everything in my apartment, it still smelled very strongly, kind of like sewage but more just like something rotten. I looked around and came across a big patch of green mold in my bedroom, just above the baseboards, and it looked like it was growing down under the carpet and smelled awful. I'm staying at my boyfriends now and took my pets with me, but I'm feeling really off, like nauseous and really tired with a headache. Is this serious or should I just wait it out? Thanks in advance.