Found mold in my basement apartment, green with white fluffy stuff?

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 also noticed that it was right below one of my windows, and I do remember one day about a month ago that I was out and left the window open and there was a big downpour - but when I came home there didn't seem to be that much wetness, I cleaned up most of it anyway, I don't know if that's what it is. I've had plumbing problems in this place already as well so I'm wondering if the pipes could be leaking under the floor making the carpet damp. 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. I'm going to contact my landlord tomorrow, but should I be concerned about how I feel right now or will it subside? Thanks