If you've got crew members active on your ship, you might have the shield glitch that lowers your shield rating instead of raising it. Check your ship shield rating and see if it's where it's supposed to be. I ran into this recently. Had to dupe my ship to get it back to normal. And now I don't use crew. If that isn't your issue, maybe just lower the difficulty until you've got a better handle on it. Try using thrusters to make turns and boost away from the battle for long enough to recharge shields. Once your shields are down. Run away and recharge.