If you want to marry your girlfriend it's unavoidable to legalize your stay because you will have to get in contact with German authorities (Standesamt for the marriage and Ausländerbehörde to get a residence permit after the wedding). You will have to submit your passport and without Aufenthaltsgestattung or any other kind of document they can easily deport you.
I highly recommend you to get in touch with a local counselling center so that they can take a closer look at your case than we are able to do. If you tell us where you are living, we can help you by researching some addresses that you can go to.
To be honest, I can't tell you if it's too late for a new application (e.g. if you apply too late, BAMF might reject you because they assume that you only did the application in order to avoid deportation) or in how far the circumstances under which you left the procedure play a role. For example, did you withdrew your application or did you just disappear? That might be of importance for BAMF when they decide to give you a new procedure or not.
Maybe someone else from this community can tell you more about it than me.