Prescribed Zoloft at my 6 week exam

Brittany
I've been having very anxious, over whelming feelings about everything since having my baby. The feelings were there before but not as bad. 
So my doctor prescribed me a low dose of Zoloft yesterday and I took my first dose today and right now I feel like I'm on the verge of a terrible panic attack. I feel like throwing up and I want to cry I was shaking but now that I have both my children to sleep I'm not shaking like I was but still feel terrible. Is this a side effect? Is it going to be perisistant? Any advice would be great.