Thoughts/Advice Needed

This might be a little long but I’m gonna try to keep it short, so bear with me....I think I’m having a miscarriage? It would be my 4th loss but never have had one this late in a pregnancy before.
I’m supposed to be 14 weeks on Sunday.
I’ve had a horrible feeling that something wasn’t right and this baby would never make it, from the beginning. I’ve been suffering from HG, extreme migraines, all the normal pregnancy symptoms (sore boobs, nausea, etc), and severe chronic pain thanks to my autoimmune issues.
Right at 12 weeks, I woke up and had this eerie feeling the baby was gone. All my pregnancy symptoms were GONE. not tapering off, just completely gone. (With my son I also had HG and was sick till 8 months, so this was strange to me). And my uterus, which I’d previously been able to barely feel, has disappeared. I can’t feel it at all. It was like my womb just felt still and quiet when before it had been far from that. A few days after that, I started having horrible diarrhea for no normal reason (no diet changes, etc), a severe backache, and lots of horrible cramping in my abdomen. I had the TEENIEST bit of weird stringy gummy brownish discharge, then tons of thick mucus as well as watery fluid discharge. That particular bout lasted 3 days, and then all that stopped.
Then yesterday it really ramped up. I had a little more of that weird gummy discharge that was brownish, and I was having a horrid squeezing backache, strong abdominal cramping (had my son naturally/no drugs so it felt like early to mid labor cramps), and I felt unexplainably weak. It lasted for probably 8 hours and I really thought that would be the start of the bleeding and etc. I slept really badly due to the back and abdominal pain. I also had some waves of stomach muscle tightening like contractions. But never had any bleeding start. Had more watery fluid and tons of thick mucus discharge. My toddler was up every few hours so between him and my physical discomfort I didn’t get much sleep. The cramping tapered off a bit around 4am and I was able to fall asleep for a few hours.
It had faded to a dull pulsing ache in both abdomen and back when I woke up. I still feel strangely weak, no pregnancy symptoms, and the cramping in my abdomen has kinda been coming and going, but isn’t super severe. I also had more diarrhea and lots of discharge this morning. There was a huge ball/gob of mucus that did look like it was tinged pink at first, but it was just barely so I started second guessing myself thinking it was the lighting but my gut says it WAS pink.
I have the earliest appt booked for Tuesday of next week to see what’s going on. (no interest in sitting in the ER for ten hours with my toddler haha).
I know loss is a sensitive and sad subject and I totally feel for all women who have suffered through it. I’m alright mentally, I just want to know what’s going on so I can prepare myself and grieve or relax and stop worrying haha.
Does any of this sound like normal pregnancy symptoms?
Does any of it sound like miscarriage symptoms?
How long does it take a later miscarriage to take place? Google says anything from immediately to 6 weeks. I’m losing my mind. I’m sorry to ask ladies to share experiences but if anyone has any advice or experience to offer, I’d greatly appreciate it! 💕