Newb first batch questions

Just finished 3 gallons of a newcastle all grain clone in the fermenter. Just have a few questions about some things that came up unexpectedly. The strike water I got to about 180 ish and once all the grains were in the cooler converted mash tun, got to 155, liitle lower than I wanted but still ok. After a long awaited hour, I sparged with a gallon of 165 temp water by lightly pouring in the gallon. Than with a container, let it run off and back into the mash for about half hour until it looked pretty clear. (maybe big sparge error there).
Brought the kettle to a boil and added the hops. I had no idea it would get the wort filled w little green thingys. I ended up with less than 3 gallons after the boil too. Should I have used a grain bag? And of course next time, more water.
I made a wort cooler with 25 feet 1/4 inch copper tubing to an adapter for the faucet. Got to 70 in about 5 mins! That worked really well!
Knowing that I needed to end up w 3 gallons, I boiled water than in a panic to add the yeast I forgot to measure the water. Once the water got to 70ish, I threw the yeast in the water, began to fill the carboy to 3 gallons and realized I had about a gallon too much so I had to toss 1/2 the yeast.
I was afraid i had too little yeast but after a few hours I had the airlock at a steady pace and all kinds of things moving around in the carboy. After 2 days the airlock is down to a bubble every few minutes. Hope thats ok.
I havnt taken a gravity reading yet, mainly because I forgot. Should I take one now that things have settled and once it stays the same for a few days its done ready for priming?
I also want to thank all the moderators,posters and owners of this site for the knowledge and support. Cheers!

I remember feeling like a one-armed paper hanger for my first several - well OK, several dozen - batches. I don't see where you made any serious errors though. So you will have beer!

And now, as Tom Petty says, "The way-yay-tin is the hardest part"

Cheers!

If you don't, try using Beersmith software. It will do all your water and temp calculations based on your input. You can set your boiloff rate, which is why you were less than 3 gallons and you can input trub and cooling loss.

Thanks for the tips, definately will use beersmith next round. I did take a gravity reading today and just a hair over 1.020. Tasted like beer! A bit bitter but hoping that will tone down after another week or so.

Just bottled this batch. FG was 5%, tasted like flat newcastle! Now to wait for bubbles