I have been taking Verapamil 40 mg 2 times a day for around 8 months (as a treatment of tachycardia and high blood pressure). But nowadays when I take the medicine I notice that my heartbeat becomes fast & experience palpitations, trouble thinking, sometimes slight breathing difficulty. Due to these recent side effects I can't take the medicine regularly like prescribed. But if I don’t take the medicine my blood pressure especially the diastolic pressure becomes high (diastolic goes over 95). Why are these new problems arising & what should I do about it? Is this serious?