The Orb - Orbus Terrarum (listened to this one every morning for a while at sunrise -- Ed: actually, predawn. I listened to the Stone Roses' debut every morning at sunrise.)
The Orb - The Orb's Adventures Beyond the Ultraworld
The Orb - U.F.Orb (these three are their first three albums but they could hardly sound more different from one another)
Edit: Steve Hillage - Rainbow Dome Musick (more Eno-type ambient)
Then there are some dub-based ones. Jah Wobble, like Eno, did a lot of collaborations (once with each other, in fact; you might want to hear it out of curiosity but I don't remember if it's any good or not). Not all of them fall under the definition of "ambient". Try his early works with Invaders of the Heart (poppier, but you'd probably like Without Judgement. The disc he did with Evan Parker is good (and jazzier), and if you're into Middle Eastern stuff, try Shout at the Devil (with Temple of Sound). But we're getting a bit astray.
I assume you've heard the Aphex Twin Selected Ambient Works albums (or at least the first one). I don't really like any of his other music but that disc is a favorite.
That's rough what's been going on, and I don't have any good advice. Obviously it's common for even good work buddies to fall out of touch after you leave that job. It's very good that you're still in contact with her; go for coffee or brunch or whatever sometime and ask her to bring a friend (you seem to need/want another). This probably won't go particularly well the first time (at least); don't give up.
In real life this is tough for me, too; I have several mental problems and I'm pretty high-maintenance (and arrogant and impulsive and self-centered, and I smoke too much pot -- maybe "flaky" is a better word); I often alienate people, though I'm careful not to burn bridges. Still, my eccentricities can be hard to deal with and I can push people away. A few friends are all you need, though. If she has a healthy social circle then that's a potential resource. The weather is probably too cold for this right now but if you (and anyone else, either her or the friend she brings along) have dogs you can go to a hiking or nature trail to walk them. Maybe when the spring comes. It's much easier to break the ice this way.
Do you still live at home, and if so, do they charge you rent? Around here housing costs are exorbitant; if you look on the bright side, you're (if you're living with your parents) saving a shit-ton of money. Use this to your advantage.
That's about all the advice I can give, and it isn't much, and maybe not all good, but there you go.
PS: a walk in the woods is free, but coffee and/or brunch and/or whatever is not. It might go well to ask your folks for a little money. It might feel lame but they'd probably be thrilled that you're getting out of the house and meeting new people.