Shit feels so good. You'll feel better, you'll look better, you'll be more capable in your day-to-day life. I've started going back after many, many months off and I'm actually kind of glad of my loss in strength, because it means I get to build it all up again. Seriously, give it a go, you will not regret it.
True although running definitely sucks way more than lifting from a "feeling like death" standpoint
Depends on what you do. The first few weeks it absolutely does, but after that just take it easy and you'll be relatively okay. Still feels like ass tho.