You were immune to the lovesick virus, and had multiple quirks (powers). Deku had his quirk one for all, he wasn't immune. Mutated zombies can disable quirks and make people weak, and vulnerable to them in their range. it's a rule.. in the hospital and in curtain places with survivors, if they get infected, they have to be put down, so no one else gets infected. Mutated lovesick people are called desperate.. they can use quirks and powers, being mutated with different abilities.