This is a very tricky question. A1S is breaking a lot of new healers to be sure, but it might also be something on your end.

Are you using STR accessories? All str + DPS stance may be excessively hard on the healer, especially if you don't have enough HP after Hypercompressed plasma to survive the auto attack. This is why pentamelds are oft recommended: It gives you survivability with the VIT while also giving you STR for DPS. Also, the tankbuster isn't the only strong attack... any extra CDs or mitigation you can do to help out, helps.

If you're using VIT accessories or pentamelds already... and feel confident with your CD rotation... well, you probably need to work with the healer to find out what they can do to improve (or, worst case, replace them). It might help if you could have experienced tanks and healers watch your group's stream to figure out where the problem might be.