What dose did you start at? Lyrica should be titrated up.
Your doctor may have given you high dose because you use Neurontin already?

Sometimes CNS side effects go away. They can be variable.
When I started tramadol, a whole 50mg made me hallucinate all night long! I stopped taking it that way and now only use 1/2 tablet, and not often. I rarely get that side effect now but last night I sort of woke up and had a touch of it. I am really sensitive to tramadol, but I had alot of pain this weekend from overdoing garden work, and needed one. (I call this effect for me "tripping").

Lyrica and other anti-seizure drugs DO have a suicide ideology warning. Getting that side effect on the first dose, is not common. I suspect it was dose related. Or you should get some kidney tests...since this drug is excreted whole by the kidneys, and not metabolized.

In any event, I'd report it to the doctor. Also look at the sample pack and see what the expiration date is. Samples are often short dated, and yours may be expired! (doctors don't often check this, like pharmacies do).