I forgot to take my pressure pill 2 days ago. Should I take 3 pills today?

No, you should never double or triple a dose. As soon as you realize you have missed a capsule, you should take another one. It may take a few days for your pressure to stabilize after you forget. In the meantime, try to pay attention to all the little non-pharmacological things that can help you control your blood pressure (drink plenty of water, limit salt in your diet and do moderate physical exercise such as walking).