Oh yeah... go eat. Stop reading now and go have a hamburger or something.
Seriously, I would drop the slimfast and add in a protien shake and a power bar. More calories and better for what you are going for. Add in Turkey, Pork, Beef, etc as well as nuts and whatnot.
Let me explain why you want to add more calories. At that low of a level, your body will probalby go into starvation mode and just shut down. You will then not lose weight and you will also not make as good of strength gains as you otherwise would. You have to MAKE SURE that you give your body what it needs to function as you are trying to get it to do.
At that height/weight, you aren't really overweight all that much. What is your body fat %? My suggestion really wouldn't be to lose weight at all, but if your BF% is high to convert that fat to muscle. Probalby much better for you as well.