Off Topic, but...
It so happens that I'm an electrical engineer and a pilot
Just a Cessna 172, but I get enough time in "the system" to have a ton of respect for the job you had. I totally understand you not wanting to transition to the civilian system though. I know a couple of ATC folks and they really look forward to retiring.
If you are pumped about electronics and figuring out how stuff works (and it sounds like you are), don't sweat the math. You'll get it. It will suck greatly, and you'll have to dig in, but once you're done with it, it's all downhill from there.
A long time ago when I went to school (graduated in '88) we had three Calc classes (1, 2, and 3) and then Differential Equations. The last one was the hardest only because it got more abstract and more difficult to visualize what was going on. I'm not a math whiz by any means so I really had to buckle down on it but did well. I'm passionate about electronics though and that's what got me through