Mold knowledge needed: UPDATED

So I currently am in the process is building a home(and should be moved in by early summer) and currently rent. I live in a fully finished basement and the other day, went to move my mattress only to realize the bottom was covered in what appeared to be black mold.

I instantly threw that bitch away, but now I want to know if that's common or if that points to the entire basement being a mold playground. FWIW, I'm currently still living like a college kid and had the mattress directly on the floor(didn't want to put together my be frame until I move into my home), but as stated, there is carpet down. I don't wet the bed nor do I spill things on my mattress on a normal basis.

Mom has me paranoid and is freaking out, which leads me here for some unbiased information. I really don't want to have to move twice in the next few months, but I also don't want to die.

I have noticed a few health things pop up lately, which I'm contributing to the mold, but I'm just needing to know if the mattress mold would be directly linked to moisture issues in the basement, or if that's semi-common for memory foam mattresses.
TIA.

ETA:
So, behind my dresser I found this gem. Would like to add this to my evidence.

What started as this(which I took a photo of the day I moved in)


Has since turned into this






Guy said "Well, at least it just looks like water damage at this point, but this spray should kill any mold if there is any there! Then we'll have someone come replace this piece of wall panel for you!"

"Uh... those black dots look like mold to me. And does that magic spray go through walls? Because my common knowledge is telling me that if mold is making its way through the wall, it's probably thriving inside of it. Not to mention we've lived here two years and that leak was clearly painted over before our arrival."

Management of my complex is supposed to be calling "today or tomorrow"
What should be my next move? Does that appear to be mold in the new photos I posted? And am I dying?