ColdCoates90 doesn't know what he is talking about (but I do love him!); artificial sweeteners, splenda, crystalight and diet soft drinks are all horribly bad for your body. Granted, some might be
better, but they have a lot of crap you shouldn't be putting in your body. I can link you to studies on them if you don't want to take my word for it.
Take it from a gymnast: Eat better (the only sugar should be from fruits and such), drink only water or protein shakes/ fruit smoothies and maybe a little milk or rice milk. I could create a 2 hour workout easily for you with just what you have to work with.
Try to do 100 pushups every day, and try to decrease the number of sets like, weekly. For example, try doing 20, 20, 20, 20, 20. Then next week 25, 25, 25, 25. Then perhaps 35, 25, 25, 15. You get the idea. Try to focus your workouts on a few muscle groups at a time. Biceps, triceps, shoulders and chest on MWF, and Legs, Back THS. You can do abs everyday
Hollow body position is really good for your abs. Lay on your back, lifting your shoulders and legs off of the ground with the only part of your body touching being your butt and the small of your back. See how long you can hold that. Sets for 30 seconds are good, but you can also scissor your legs, rock back and forth, or tuck your legs and crunch your body... there are hundreds of things you can do.
I've got plenty more if you're serious. Hope I helped