300 mg is a hefty dose of temazepam, Isaac. I know this is an old post and you've been around since but next time, try to be more careful with dosing drugs you're not familiar with. We'd like to see you stick around!
I understand that this thread is a little bit old, but this is essentially "not Harm Reduction" in action. If you have the notion to question your mortality in the first place, do so before ingesting the drugs and not after. I understand that I'm probably a little bit more open with my feelings than most people, but am I to assume that this is Depression -> Suicide -> Rescue -> Attention deal?
If so, we are happy to do our best to keep you alive in the interim, but we are also here to provide you with the emotional support that is often required to get over some of these hurdles we face.
Getting down to brass tacks here, Pregabalin (Lyrica) is a Gabapentinoid and Temazepam (Restoril) is a Benzodiazepine. The parent groups when used separately are tolerated practically ad infinitum. The average person can tolerate dosages exponentially more potent than those even stated here without necessarily worrying about a misadventure. When they're combined, there is not a ton of information, but you should safely assume that by combining these two seemingly harmless drugs, you are possibly creating a toxic situation in vivo.