Should I Wear My Retainer Only at Night?

The odds are that your current retainer will not fit after four years.  I would see your orthodontist and have him/her evaluate it.  Assuming that it no longer fits, you can have impressions taken for a new one.  Perhaps a clear retainer could be made so that you could wear it longer than just at night initially. Good luck. 

Hi Brittanny...you wore your retainer for one month only before you bailed! Fast forward to four years later and at 19 you want to start wearing the same retainer again. Believe me, your teeth have moved in the last four years.  You should see a dentist for a new retainer.  If you had been compliant and wore the retainer as your dentist suggested, your old retainer might work. Please see a dentist and have a new retainer made for you!

You say that you only wore you retainer for a month before giving up on it.  In my opinion there is no way the retainer is going to fit still.  You need to see a dentist to fabricate a new retainer that probably can be worn only at night.  I would assume thought that your teeth had shifted at this point.