You definitely need to take the Mirtazapine and Pregabalin as directed, every day. The Mirtazapine is probably meant to be taken at night and the Pregabalin is probably taken twice a day. Check the labels though for your specific instructions.
I've never taken Zoplicone but again the label should say.
Steer well clear of alcohol for the next four weeks or so while you adjust to the meds, and any other self-medicating you might have been doing.
Remember we are here if you need support.