Help with anxiety after quitting Zoloft?

I'm 18. Since I was 13, I was on Zoloft for generalized anxiety disorder and the depression that accompanied it. I was never a fan of being medicated, especially at such an early age, and I've recently quit. While on the medication, it worked for the most part with the side effects being a mean headache in the morning until 2 hours after I'd taken it and slight weight gain. I've been off the medicine for about a week and a half now and my anxiety symptoms are returning. I constantly feel tense and worrisome, etc. If someone doesn't text me back, I feel worried as if I did something wrong, I constantly analyze my relationships with my best friends and worry myself to death about the possibility of losing them, even though I know I've done nothing to upset them. When I woke up this morning, I just stared ahead for 30 minutes, not wanting to get out of bed and finally got on Y!A to ask for help with these feelings. Is there anything I can do to help myself without the use of medication?