Get swiftcast ASAP. Your THM is level 17 so it would not take long at all. There will be times your pet will die. Spending 10 seconds hardcasting your summon or taking the dps/healing nerf is too much of burden on the raid. Plus you can help your healers by rezzing for them as well. Use "sustain" on your pet whenever you are expecting any aoe damage or you see it getting hit. Place your pet where it can dps while taking little damage. Make sure you reposition your pet if it gets knocked out of range.