See your GP you may need to up your dose to either 150 or 175 to control it
What thyroid level is over 150? Is that TSH? If so, is that the only thing you've had tested? What about Free T3 and Free T4? Those are the actual thyroid hormones. If you've had those tested, please post the results, with reference ranges, as those are much more telling than TSH, by itself.
What "crazy" symptoms do you have?
How long have you been taking the 125 mcg Synthroid?