PE can be quite stressful. Try taking a couple of rest days and then evaluating.
There is another issue which can cause problems. When you are paying this amount of attention to your dick, you notice stuff that you wouldn’t otherwise notice. It’s just like when you buy a new car or phone or whatever and suddenly you see loads of them all around you. This can lead to problem #2, where we assume the stuff we notice is bad and worry about it, causing actual bad stuff to happen. The mind is pretty powerful, if you notice you have flagging erections one day, you may then worry and this can cause a negative loop.
Also it’s worth focussing on your routine and making sure that you apply yourself with equal vigour. Maybe the days you don’t see extra hang are the days you crammed PE in at the end of the day when you were too tired.
Of course, it could be none of those things and you could just be working too hard.
I don’t know how strict you are with your measurements but if you want to evaluate growth effectively, you have to take superb measurements and keep a good note of them. Within 3.5 weeks, it would be nice to see measurable gains.