Mold or Fungus in my garden
Hello! I started my first garden in May and I'm having some issues I need help with. We bought peat moss, compost, and miracle gro organic garden soil mix, and we mixed all 3 together and put it in our garden box. At first everything was sprouting amazingly well, but after a month or so I noticed some wilting on my jalepeno, tomato, and cucumber plants. I thought maybe they needed more water so I began watering heavily every day at the roots (I think this was my first mistake). A few weeks later I noticed a lot of mushrooms in my garden. A few weeks after that I found white mold on the bottoms of the jalepeno leaves and all the jalepeno plants were covered (and removed) eventually. My carrots didn't seem to be growing much past the month mark and when I dug them up and tilled the soil, I found huge clumps of mold or fungus (I don't know) but it smelled awful and made me sick to my stomach. I have turned up the soil in different areas and some places have massive clumps of this mold/fungus under the soil and some areas don't.
Is there a way to treat this soil or should I replace the areas that are completely saturated? Is this a dangerous issue like possibly black mold that would make eating the vegetables dangerous? It's definitely causing my plants to die and now that I'm trying to plant new seeds, very few are sprouting and those don't seem to last long.
I really appreciate your time and help. I would love to keep this garden going, but I'm pretty discouraged