Hi Yaaraud – welcome to the forums! And thanks for providing this level of detail, it’s super helpful.
I dilated for several months as treatment for my vaginismus and in my experience, I only needed to dilate once a day, but it really helped to do it EVERY day without taking any days off. I recommend actually continuing to dilate during your period – it might seem “gross” to some people to do so, but the added lubrication often actually makes it easier to insert the dilators, and as you have seen, taking several days off often means you have to work back up to the larger sizes once you do return to them. Continuing to dilate through your period will mean you’re way more likely to be able to get to the fifth dilator.
Also, what brand of lubricant are you using? Water-based lubes often dry out quickly so I liked to use a hybrid water/silicone lube (these don’t damage silicone-based toys or dilators. The Sliquid brand is especially good:
You likely won’t always have to dilate every day, but when you’re first getting started it really helps lock in those gradual gains and help you move to bigger sizes!