It wouldn't hurt to visit your doctor, Memphis.
I'm sorry you're going through this!
What you used to eat might have masked the symptoms of a health problem that's only showing up now. Or you may be sensitive to Splenda. Or, perhaps, there's something else going on...like you started drinking more coffee when you started SBD or something like that...and it's affecting the headaches. Keep track of what you're eating/drinking and how much, as close to exact as you can, then go see your doctor and see what she/he says, okay?
Also, posting a daily menu here might help us all to help you figure out why you aren't losing. Hope you can resolve this soon!