Jesus had it, the 'dark night of the soul', I suppose, on the cross: my God my God why have you forsaken me.
Which I assume could mean - where are you, I've lost you.
Agreed, it could suggest that he hadn't lost his belief in God but that he felt forsaken, abandoned. You thread title says you have lost God, which could suggest a similar thing.
I wouldn't take it too seriously iiwy. I am not being flippant. 'Feeling' you have lost God is, ultimately, an emotion. Devastating, of course - I feel for you. But if you have lost religion, rote, mentally relating to God, then you've not necessarily lost him entirely; you're probably gaining more of what he is about. But the dark bit is uncomfortable and can be very distressing. Try not to take it too seriously if you can.
Because God hasn't gone, that's not possible. You're probably shifting gears which will be his doing. So good for him to be leading the thing. Alarming, of course; especially as we are so used to driving it all, driving everything. Wonderful (and challenging) to find out we don't have to, that the relationship he wants he is perfectly capable of carving out - whether we are knowingly on board or not. Painful, though - as he knows it will be. Devastating and desolating. It's not possible to nail your own self to your own cross - always a spare hand - so it's a good job he knows how to do it.
iiwy I'd go with it. Which will take time if religion has defined you. Enjoy and explore being 'Godless', enjoy losing the bits you never enjoyed but felt you 'ought to' (good to get rid of those, I find). Enjoy sloughing off the tonne of guilt (that was never meant to be there) and obligation (ditto). Spread out.
Well, if you want to interpret the experience within traditional religious thinking then I'm sure you could describe it as "a dark night of the soul" - but there are other ways of looking at how you're feeling now too (as I'm sure you're aware)
whatshapeisthisnow how about getting some books on various topics and see where they take you? You could look at the history of the Bible, some Richard Dawkins, books on other religions, Christian books on faith and how we feel, etc. Also perhaps visit one or two other churches for a new perspective. I think it's totally normal to question one's faith and to feel differently at different times.