Swimming in a Wetsuit is exhausting

Swam in a wetsuit for the first time today, and have an Olympic triathlon on Sunday.

It’s a Huub - Mens Alta 2:4 Wetsuit, so not exactly the worst but it’s not world class.

It felt great in the legs, much more buoyant, but my shoulders were absolutely exhausted, is this normal?

My normal time is around 2min/100m and managed to keep this if not slightly slower but I couldn’t seem to swim more than 200m without having to stop.

Is this normal? Should i see if it’s possible to not wear a wetsuit or is it a first time thing and my arms might get used to it if I swim a couple more times before Sunday?

Appreciate any thoughts