a horrid habit

so stress has been on high-frequency lately and thus, sadly my awful habit from my preteens has returned :( last semester. grad school applications. first apartment. boy in med school. independence. let's be real...this is lots to handle and i found myself suddenly nibbling away and every time i look at my hands i want to hurl over and cry. it's so embarrassing!! and i am constantly having to cut them to even them out or try to make them remotely better....but then when i stop for a few days i start again as soon as the stress hits. i guess it's better than most habits and from my research (i'm a dork) there's nothing harmful except for awful looking nails...and that's enough for me. any tips on quitting this horrid habit?! i'm all ears!