I only had an issue because I was taking an iron supplement at the same time which also can further cause constipation. I stopped taking that and it resolved my constipation issues.

I'm not too sure what you're referring to with a "write off day". I am on the highest dose currently and don't have this issue. I maybe get some sleepiness the day after taking it but I can still do things. However that effect has also subsided a lot after taking it for long over.

Every medication will have pros and cons. I'm having huge success on the medication and the slight issues I have are a worthy tradeoff personally.