Hello,
I just happened on your post. Your stats are not unlike mine except I was a little heavier to start with and I'm still somewhat heavier than you are after losing nearly 17 kg and putting 4 (well nearer 5 of them) back on, very gradually over two years or so. My goal is higher too, though right now it's receding into dream territory.
To the point, frankly I never experienced this. That doesn't prove anything but I wonder whether it's really related to your way of eating. It may be an infection or something else.
If you are really doing what you've been doing for 90 days and this has only just happened, I suggest you try to eliminate all other potential causes first.
You are doing great. I hope you feel better soon.