There are so many anti-depressants out there, that it is more like a trial and error process in finding the one that works for you with the least amount of side effects. Believe me, I have tried at least 15 over the last 10 years.
If you are determined not to seek professional help, than you could try the St. John's Wort ( as suggested by leastofthese), but check with an herbalist or pharmacist, or do research to make sure you understand it. Also, there are herbs like Valerian root and Kava Kava that are supposed to help with anxiety, if that is one of your problems too. Again, make sure you understand them before taking them.
I hope his helps.
Peace, Love, and Prayers,
Michelle