You're feeling dizzy because you're starting to panic. Relax and breathe. 2 Atenolol
is NOT an overdose, it is just you took a little too much. It will take time for your body to clear it. In the meantime, rest, relax and drink fluids. Your current pressure is completely normal. Try only taking your medication at a certain time each day, this way you'll know you took it and won't take any more.