Are u just starting out on thyroxine? Looks like the doc is just trying to figure out what the right dose is.Once u get to the right dose it should stay the same for most of your life unless your thyroid dies off some more.I've been on the same dose for 10 years. Except when i switched to a different brand I needed a higher dose.
Your doctor appears to be trying to find the appropriate dose for you. You went from Hypo to Hyper because of too much levothyroxine.
Did your doctor run a thyroid antibody test to determine the cause of your thyroid problem? If you have elevated antibodies, you probably have Hashimoto's Thyroiditis. If the antibodies are not elevated, the doc needs to determine why you have a thyroid problem. If it is Hashimoto's, that can cause you to swing from Hypo to Hyper.
Most newly diagnosed patients have to have a few dosage adjustments before they level out. You should have your levels checked about every 6-8 weeks until you level out. When I was diagnosed, my doc ordered an ultrasound of my thyroid and then another 6 months later.
After your TSH levels are where they need to be, you should probably have them checked every 6 months to a year.
If you feel your heart racing, your dose may be a bit too high and you should call your doctor.