IBS or not...???

Male @ age 66 here.
Since I passed age 50 I always had a slight abdominal pain and cramping with gas and bloating.
This happened when I quit smoking and started to put on a lot of weight around those years.
6' and 180lb guy turned into 245 lbs now.
A little over a month ago I tried carnivore diet for a week. Right around that time I began to have a little extra cramping, bloating, gas, diarrhea with significantly increased abdominal pain right after I finish a meal.
This was happening even after I follow fodmap diet or even how little food I eat.
After a little meal, I bloated and I hear loud noises as if water rushing inside my body from section to section. Most of the times after these symptoms I feel to go to the bathroom with urgency followed with either diarrhea or very loose bowel movement.
Then feeling of relaxation comes over for a little while until I have my next meal. I sleep ok about 7-8 hrs a night.
Since almost a month for the first time in my life I never had a solid bowel movement.
When I told about these to my Kaiser Permanente doctor, his opinion was "it seems carnivore diet doesn't agree with you"...
But that was 3,5 weeks ago and I don't think 1 week of carnivore diet would mess me up so much that I'll have a month long IBS-D symptoms.

I just emailed him again and basically begged for seen by a gastroenterologist.

Is anybody experienced similar issues as their IBS-D starting such suddenly at an age like mine.
Gas, bloating, abdominal cramping, nausea, diarrhea, and 3-4 times a day loose bowel movements with suddenly oncoming urgency?

I wonder if I always had IBS and for some reason if it got worse or if this is something different?

Just wanted to hear your thoughts and experiences.

Stay well...