hi ggglimpopo, hope you're hanging in there.
Re. the salbutamol -- dd2 was breech at 37 weeks and I had a procedure called external cephalic version (physically turning the baby).
They gave me a drug related to salbutamol, called ritodrine, which was intended to relax the uterine muscles, in this case to facilitate the turning, in your case presumably to weaken the contractions.
It did exactly what you describe -- made my heart race, face flush and very trembly and weepy too in fact. Apparently this family of drugs is related to adrenaline, which makes sense. It was unpleasant, but apparently completely normal reaction and not dangerous.
Take care