Grub Necessity

Okay, I've been planning on starting a blog for a while now, trying to put together what I actually wanted to do was my biggest dilemma.  So I finally decided to talk about diet, because I'm obsessed with my weight, it's what I think about every day.  I have had a weight problem since I was in 5th grade.  I've been on every diet imaginable from the liquid diet to the grapefruit diet to weight watchers and many others.  So it has come down to counting calories and weighing myself a few times a week.  I think weighing once a week is probably the best so you don't see the ups and downs of the every day weight as it becomes too discouraging.  My doctor says try eating 1200 calories a day, well that's virtually impossible if you don't write down everything you eat.  Then you need to find a good food calorie counter, so you can look up how many calories are in that "big mac" you just ate.  So now I need a something to weigh the food on, because I can't eat a 5 pound burger or that may be the only thing I'm eating today.
So any good suggestions as to apps for calories and exercise?  I've found a few but can't decide which one to use;  myfooddiary, dietdiary, sparkpeople, etc.  finding one that does exercise and food would be great.   
That's the next thing exercise, I have never been big on exercise.  I've gone through every exercise program known to man.  My sister and I used to walk the track at Coleman Jr High, then we did Jazzercise together, then she moved.  It's a good idea to get a partner to exercise with because it makes you go.  So then I had to find someone new, so I did over the years.  I worked out at a gym with body builders (that was fun, but not exactly what I needed).  I did some other things along the way.  Now I've joined a city gym and hired a personal trainer.  He works my butt off 3 times a week and then I try to take some of the other classes the gym offers on the other days, then on the other days I walk with my roommate. 
 So my plan is to post what I'm having for my meals and exercises that I do during the day.