"What is the best strain to calm you down, not make your heart race and get you shaky?"
I love this question. That tends to happen to me as well when I have too much THC. You may want to try a strain higher in CBD such as Canna Tsu or Harlequin. Both of these will have a calming effect and if you smoke a bit will still have some psychoactivity. Focus on strians that are 1:1 ratio or even higher in CBD. I tend to like a 3:1 or a 4:1 which is CBD to THC.
I hope this helps!