Just keep on keepin' on! You'll make it there...you're body wants to be there, but it probably just adjusting and getting into the swing of things. The initial period was probably just shock.
I think everyone gets tempted by "diet" pills because it's the easy way, so to speak...keeping your eye on the future is hard, not only with weight loss, but with life in general. You've done fantastic. If I'm doing my math right, you've lost around 5lbs a week (over the 143 days)! Almost everything written talks about loosing 1 to 2lbs a week is great progress!! So sit on that for a while...5lbs a week is fantastic! Keep it up and you'll get there. And enjoy the process!