Yeah, most quick and dirty courses are "intro to project management" or "foundations of project management" types of courses just meant to give people bare bones fundamentals.
A 3-day program won't get you much. And I doubt it's the type of certification that is recognized by employers who are seeking accredited / certified project managers. Getting legitimately certified in project management is a lengthy process and usually also involves a practicum of some sort. Put it this way: you'd have a better shot at a job than someone who has zero experience and zero training in project management but you wouldn't have a better shot than someone with plenty of experience in project management despite having zero training.
Keep working, do accredited courses at night or on weekends so you gain credits towards your PMP certification, get certified, look for promotions or other jobs that require PMP certifications.