Ahhh, welcome to the wild world of PM...

First, there's the 'formal' realm of PM wherein the powers that be will go on for hours regarding the Triple Constraint (Scope, Schedule, and Cost) that in lay terms is "What work needs done, when and at what cost?" and usually tack on the two very important but often overlooked elements of Quality and Risk (plan quality in rather than scraping or reworking after poor quality work and what are the risks and what do we do to prevent, avoid, or mitigate them?) They'll also provide wisdom in cliche form: Plan the Work and Work the Plan followed in short order by the corollary of Fail to Plan, Plan to Fail. So... the heavier emphasis is on planning in theory. In the real world we often don't have too much time to plan and in your case, none or precious little.

So, what to do NOW? Document, even if you feel you don't have time - make some notes, get them into some sort of template that allows you to show what work was planned, what cost, what schedule and then use a similar format to report progress or performance. This will look totally legit if you can compare it against the original plan (also called a baseline) in terms of % complete and if possible, show variances against the plan in terms of cost and schedule. For example:
Budget: $100,
Actual: $110,
Performance: $95
Cost Variance: $10 overspent
Schedule Variance: $5 behind schedule
Narrative: "We had planned on spending $100 (and getting $100 worth of work) but spent $110 to do $95 worth of work."

If you can provide an executive type of report along those lines, you'll be seen as the awesome knight who dares to visit the trenches but cleans up nicely enough to visit the throne or board room and speaks regally.

Finally, with that documentation, CLOSEOUT of the project is kind of like cleaning up and shaking hands that the deal is done. Complete a final report, put all documentation together in a file folder or box, and have whomever is the big kahuna sign off on 'delivery and acceptance, tranisition to maintenance, transfer of ownership, etc.' and then decide if you want to continue in the PM world. [Linked Image]