The results of Diazepam and Pregabaline are related but with different mechanisms to do it. Pregabalin doesn't affect your GABA Receptors directly.
Tramadol works in another way but you chose 3 substances that increases risk of respiratory depression if combinated.
Pregabaline + Alc made very loose, better social abilities. I think BZD and PGB could cause similar effects. Treat this combos with caution, too!
But i suggest not to add the Tramadol. In difference to the others it could activate you with soft euphoria and well being. Combining it with inhibiting drugs could be more dangerous and propably a waste of Tramadol.