I don't know anything about Zoloft OR Adderal, except that both medications have tremendous side effects, and the long-term effects aren't even being seen, yet. 

Aside from that, the magnesium filler could have been expired if the magnesium had been sitting around for a long time.  Do you have any coping mechanisms to deal with the anxiety, yourself?  I mean deep breathing, or EFT tapping, or "getting into the Now."  And, I will say this with 100% honesty that I thought that all of those techniques were hocus pocus until I actually practiced them and made them second-nature.  Breathing, alone, is a HUGE management tool.  Perhaps, taking in foods that are high in magnesium might work better for you  - it's just another option.

I've been suffering from PTSD for over 3 years, now, and my panic/anxiety attacks were so severe that I ended up in the emergency room on several occasions with the belief that I was having a heart attack.  So, I completely understand that anxiety issues.  There are many, many management techniques for anxiety, and I'm sure that there will be many responses about a few of them.  But, whatever you do, practice several of these whenver you can - when you are calm.  In that manner, you will learn something similar to muscle-memory, but it involves thinking processes instead of physical activities that you don't even think about when you're doing it, like driving or writing, etc.  The more you practice a technique when you're calm, the quicker you'll be able to practice it when you first feel the anxiety bubble blowing up. 

Best wishes to you