It’s probably not just your shield, post your build on this forum and we can give you some advice. I suspect you are not running a “Drake” (2x EPTx) or Aux2Bat build, and you’re not buffing your shields in any way (use EPTS, Reverse Shield Polarity, Science Team etc etc). There are many “tricks”.
Off the bat, if you need a good shield, any purple MK XII-XV Resilient shield should do – but barely.
The Fleet Resilient shields are still solid, but the best ones are usually a two or three set combo – the Sol Desperate Defenses has a bonus clicky that will give you a quick heal. There are many others, but show us your build and we can tailor it to your favorite playstyle 

"Boldly bashing Borg to bits since 2012..."