I agree with @Anonymous in that you need to amend your prior year tax returns.
In addition, you need to make sure you understand the K-1 and in particular the presentation of Section L; the capital analysis.
The capital analysis presentation is noted by which box is checked in that same section.
If this is anything other than tax basis, you will need to calculate your tax basis in order to determine your overall gain or loss.
A negative ending capital account balance will only be treated as a gain if you have truly received distributions or took losses in excess of your tax capital account. That would be unusual as (1) this is most likely a passive activity and losses limited to passive income, and (2) unlikely you would be at-risk for losses in excess of your tax basis.
I also agree that it would be in your best interest to sit down with a tax professional to work through this matter.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
