Golden Aggression Post Spay

As per title my Golden (1y 5m) was spayed about 12 days ago.

We had her second post-op check yesterday and the vet advised to keep her resting until next week due to some minor inflammation to her muscles underneath the scar.

We explained that she was struggling with energy (she was walking 5mi+ every day prior to surgery), and the vet prescribed Gabapentin.

For the last two days, since she started the gabapentin, she’s been more aggressive / bitey than usual (she’s always been a bit on the mouthy side, but not usually with significant pressure).

We’ve been restricting walks to <20m, all on lead, in the area local to the house, but she’s pushing for walks / toilet (so far about 120m today).

Is this typical for high-energy breeds / goldens or is the aggression / biting significant?

This is my first dog (though not my partner’s, although first golden) so I have fairly little reference / experience.

Appreciate any advice, and thank you for reading (it ran on a bit, apologies).