Pregabalin will make you feel drunk and uncoordinated. I wouldn’t advise taking it with another drug as it can get messy. Starting dose would be around 75-150mg. I wouldn’t advise taking more if it was your first time. Also be aware that it takes quite a while for it to take effect, I’m talking 1.5-2 hours for me personally. Does it feel like diazepam? Not for me, diazepam relaxes my body for a short while, but again, I metabolise it very quickly so I only use it for muscle spasm issues.
Tapentadol I’ve never found to make me feel “high” but I metabolise it very quickly so I may not be the best person to answer that question. From what I’ve read on the board some people enjoy it and some people don’t. If you do a search you will find threads on tapentadol, I believe we even have a mega thread on it. Beginning dose is around 50-100mg.
We also have threads on pregabalin you might find useful too.