advice on giving sub-q fluids?

We had to start on sub-q fluids today and me and my partner just did our first go of it. It was really hard to see my cat yelp and cry. I know it’s hard the first few times you do it but I’m so worried I’m doing something wrong. We watched videos on it, the vet walked me through it, we even bought a swaddle that’s meant to help restrain the cat (we tried without and she wouldn’t stop moving).

So first of all, I’m worried when we restrain her that the fluid can’t spread out and has nowhere to go and I’m scared that’s painful. second is that after we finished, I removed the needle but couldn’t find where I had placed it in the first place. I’m the videos and when my vet showed me, they pinch the site where the fluid went in to help it close. I couldn’t find it and I’m worried it all drained out? we did it about two hours ago and her back is still wet. Lastly, her demeanor changed drastically after giving the fluids. she holed away in her heated bed and hasn’t moved since. I’m going to call the vet in the morning but I’m so scared we did something wrong. and if it all drained out it’s for nothing.

has anyone had a similar experience?