Exercising without medication

So I've been off the beta blocker medication for a week now and I've noticed something while exercising. It started two days ago when I was on the elliptical. I was sweating a lot more and my heart rate was a lot higher, and I was finding myself struggling with incline/resistences that I had previously found easy or acceptable. Two days ago I just was like "huh, that's weird." Last night at Zumba I thought I was going to die. I had sweat pouring off of me, I couldn't catch my breath, and I was pretty sure I was going to have to quit halfway through the class. That;s when it dawned on me, that without the beta blocker my heart was actually moving into a fat burn stage, and did I ever move into it. Tracy, the Zumba instructor stopped in between songs twice to check my heart rate, the first 30 seconds after a song ended I was averaging 15 beats in 5 seconds, that's like 200 beats per minute, Yikes! She said after 30 seconds though it dropped to where I would average about 160 beats per minutes. Tracy thinks I might start seeing better results on the scale now that my body is actually recognizing that I'm working out... and if you'd seen how glowing I was you'd know I was working hard. I've been on this exercising kick for 7 months now and I've never felt like I worked harder than last night! Tracy also worked Abs and Arms before Zumba, so I'm feeliing a little sore everywhere. Sore has never felt so good. I'm totally excited for Saturday's weigh in, to see if my results are any better off blood pressure meds.