I think you're on the right track with pursuing a medical option such as SSRIs to assist with the chemical imbalance you're experiencing. All the exercise, eating right, sunshine, and vitamins/supplements in the world won't work if you are truly having a chemical issue in your brain.
I applaud you for knowing and admitting that you "feel like you need to get better". Not everyone in your shoes can do that, so your courage is amazing.
Understand that many SSRIs (selective serotonin reuptake inhibitors) come in a wide variety of dosages, so you may only need a little bit of the drug to make a major difference. Sometimes it might take a little bit to figure out which one works best for you and what dosage. Many people take SSRIs with little to no side effects - well, other than feeling a ton better about life!
Don't let the stigma of mental health issues and depression keep you from seeking treatment and medical management. If you broke your arm you wouldn't try to reset it at home and then splint it yourself with boards and ties - you'd go see a professional. The same thing applies for depression.
Also understand that you may need to be on an SSRI for at least 6 months. The relapse rate for discontinuing the drug before 6 months is 47%; after 6 months it drops to less than 15%. Finally, realize that it may take up to six weeks before any positive effects are felt - the drugs in small amounts take time to work on the chemicals in the brain and get the right amounts going and get them going to the right spots.
Best wishes and know that it is possible to get through this, even on meds. You may surprise yourself by how well the right medicine works for you :)