Can clomipramine 75mg + buspirone 15mg + pregabalin 150mg be taken together?

Hi, dima!
This is the report from the Interactions Checker:
https://www.drugs.com/interactions-check.php?drug_list=702-0,441-0,1937-0
Primarily the combination can cause dizziness and drowsiness in some users but you'll know that after taking it... find out if it'll affect you before you drive, etc.
There is one major interaction called serotonin syndrome which can be serious if not treated early on. It's a rare condition and as the blurb says your doctor likely feels that the benefits of taking these medications together outweighs the risk.
This link goes into details that you should be aware of so you can be on the lookout for any symptoms.
https://www.drugs.com/cg/serotonin-syndrome.html