Mine was about 18 months all told, 2 cortisone shots and a lot of physio. I have about 90% range of movement on that side now, this was about 5 years ago.
Thought it was happening on the other side last year and got very down, but that was bursitis and had one injection and cleared within 4 months thankfully!
There was a good FB support group I used, Frozen Shoulder Friends I think it was, lots of hints and advice plus understanding. When it's in the freezing stage the pain can be horrendous, I used to wear a sling sometimes in crowded places as I was so paranoid about getting it knocked. Family thought I was nuts but turns out lots of people on the group did the same.
It was an awful time, I couldn't drive and lost my job, couldn't claim any kind of sickness benefit as I had one working arm. It does get better though, keep asking for help from GP, physio etc and most of all be kind to yourself. Don't beat yourself up about not being able to do things, if you need to go and lie down and try and sleep with a heat lamp on your shoulder then that's good - getting yourself feeling better trumps everything else, it took me a long time to realise this and would try and still hoover round or mop floors - that stuff can wait!
I also bought a contraption that could hold an icepack/heated pad in place which helped a lot - just needed someone to help me get it on and off! Oh and bras - ended up buying some stretchy crop top things that I could step into.
Oddly I'm far more tolerant now, if someone is say packing really slowly at the checkout in front of me, I'm far more empathetic and grateful to be recovered.
Hope things improve quickly for you