It sounds like you have a good chance of meeting the requirements -- I can't be 100% certain, obviously, since I don't know exactly what you did. But you don't need to have the title "Project Manager" in order to have enough project management experience to qualify for the PMP exam.
If you have a bachelor's degree, then you
need a total of 4,500 hours of project management experience before you're allowed to take the PMP exam. (You can see how PMI verifies this information from
this post on the Head First PMP forum.) Those 4,500 hours don't need to be consecutive, but they do need to occur over the course of 36 months. But they do need to include the kinds of activities that project managers do -- which means they'll fall into the 44 processes that are defined by the PMBOK(r) Guide.
Did you do things like hold team meetings, report your team's progress, plan the schedule, define the scope of the project, deal with budgets, work with subcontractors or customers, perform quality activities (like
testing software), do risk planning, or manage communications? Those are things that project managers do, and you'll be asked how many hours that you've done each of them.
If you're still not sure, I recommend filling out the application to take the PMP exam. Don't send it in yet -- just start filling it out online. If I recall correctly, you'll be asked how many hours you spent performing each individual task. That should give you a good sense of whether or not you meet the requirements.
