Talk to a doctor about going back on the Zoloft, i.e., the dose to start onto again. I'd stick with the lowest dose that you need to feel normal, unless the doc says to begin at 100 I would taper up more slowly than that.
People go onto SSRIs because their ability to retain serotonin in their body is malfunctioning -- it's a physical lack, not a judgment of character. It is like needing to have insulin shots because you have diabetes. As such, there is nothing wrong with taking an SSRI. Possibly the need for Zoloft does fluctuate over a person's life, if the body regains the ability to retain serotonin again.
That all said, some research suggests that exercise works as well as (or better) than SSRIs. So if you really want to give it a fair trial without a lot of antianxiety meds, go into exercise in a big way. But give it a fair trial, really do exercise, if not every day at least three times a week, enough to sweat.
It sounds like you definitely still need the medication. Call your doctor and explain what you did, he will understand and tell you how best to get back on the proper dose of the Zoloft. For many of us medication is a lifelong thing, as stated above anxiety/depression can be like any other illness requiring daily medication to control the symptoms....and that's okay. Some have a "root cause" for their anxiety and/or depression, normally something traumatic from their past which was never truly dealt with. Seeing a therapist can help you learn if this is your case and if so, you can learn what that his, deal with it and ease your symptoms. Don't get caught up in feeling because this is a "mental" issue that you should be able to handle all of this on your own....we rarely can. Therapy can teach you so much about yourself as well as coping techniques, and you owe it to yourself to learn if there is a root cause for your depression/anxiety. If taking medication allows you to function normally and have a happy, fulfilling life, then it is well worth it. Call your doctor for guidance and go from there. I wish you all the best and hope you feel better real sonn.