Some forms of food poisoning can cause miscarriage. If you think what you had was food poisoning I'd suggest you get checked out ASAP.

I'd also be laying off the junk food. Researchers have found that high intake of trans fatty acids (the junk food you are referring to is very high in this) in pregnancy interferes with the enzyme needed to produce fats that are essential for the structure of the brain (your growing baby's). Just one of the reasons doctors recommend a healthy diet when pregnant.