It's been a while (several years) since I experienced this, but if I recall... yes, it is normal. Unfortunately, it may take a few days to level out.

Which side effects are you noticing?

If it is the "shakes" and racing heart, I would try to cut back on your caffeinne (spelling?) in take for a bit.

Definitely consult your doctor, but this is what I have done in the past...

If it was too overwhelming for me, I tried taking a lesser dosage for a day or two (i.e. cutting pills in half the first day, and then taking half in the morning and half at night the following day). I had to ease back in.

Hang in there!