Swimming fitness classes

i'm headed to the gym in like.... 3.5hours to do a "deep aqua jog" which is an aqua fit class but with added jogging techniques in the water.

been running high all day due to hormones, and i'm wondering what i should do before the gym to keep myself from going low. swimming always wears me out fast(probs cuz im not a great swimmer), so i wanna make sure i'm not gonna go low, but i would LOVE to come outta it with a normal bg.

 

suggestions?

 

if i enjoy it, i think i'll try doing it once a week, since it seems like a good workout.