I'm thinking of taking a pre-workout to help get me thru the intensity of these new routines..any suggestions for one that doesnt make you jittery?

I have been involved now for 8 weeks in a body transformation and only dropped 6 lbs and 2% BF, I eat clean, log and consume on avg 1600 calories, I weight train with a trainer twice a week and usually do 4 days of cardio 30-45 min sessions. What gives? why am I need seeing more change than this? any advice on how to drop my BF% ? I need significant change by Aug in order to be considered for winning this challenge. 

All input is appreciated! 

I need some help and suggestions for managing thru tendonitis

 in my elbow and still getting thru arm workouts..
I am novice when it comes to this stuff. 
 
Any advice? 
Thanks! 

I joined this site about a week ago in hopes of finding 
the switch that would kick my ass in gear again to get to 
the gym  and start eating right. I have come to terms 
with being an emotional  eater and lately I have been 
on a serious roller coaster ride. My oldest daughter 
who is 20 and mother of my grandsons suffers from 
depression and is bi~polar. she has attempted to take her own life
 twice in the last 3 months and I will tell you it is such a difficult
 thing to know you as a parent cant fix it. Not to mention 
my grandmother who is my inspiration and hero 
is dying slowly and painfully of 
Alzheimers and not expected to live much longer. 
 
last yr I lost 55lbs and got in the best shape of my life, I ate right I 
exercised and made no excuses. I look in the mirror today 
and see the 20 lbs I have put back on from stress and 
emotional eating in what seems like overnight. 
I  have been a quick fix girl most of my life and refuse to go there again.
I will conquer my battle with stress and continue to read so many 
amazing stories of success and motivation that help me find and 
fuel the fire within me to be among them.  my goal is to 
again be in the best shape I have yet to see and lead a healthy
 life that will take me off this roller coaster of weight loss\gain.
I know somewhere under this jiggle is a solid form, I feel it 
every time I restart working out and rediscover the muscles
 i knew i had and a few I didn't existed..
 
 
Thanks to all that post their stories 
and their successes!