I had a similar experience after pretty heavy MXE use. I slowly used more and more over a period of several months, until I was using it for 4-5 days straight, taking a few days off, then starting again. Eventually I would up manic and somewhat delusional, barely sleeping at night and constantly wandering around doing mostly pointless tasks incessantly. I also lost a lot of weight (went from about 72 kilos to 63 - 64). Eventually I had to be given antipsychotics for a week to cause the mania to abate, and it took about three weeks (after completely stopping MXE use) for the mania to fully go away.
I regained the lost weight pretty fast, but went through a period of depression for a while after that. I´m not sure how directly the depression was related to the MXE use, as I´ve experienced many depressive episodes before, including before I had ever used drugs. Also I went through some life changes around this time that were pretty distressing. But from what I understand it´s pretty common for depression to manifest after mania, so the MXE/mania were almost certainly a significant contributing factor.
Another side effect I experienced were what seemed to be severe withdrawals upon stopping the MXE use. This didn´t happen until the very end, when I was using 100mg or more a day for multiple days in a row. I would stop abruptly, and about five days after stopping use, I would get very sick. Lots of vomitting, shaking, a horrible cold feeling that wouldn´t go away no matter how warm I was, and muscle weakness and aching. This lasted a little more than 24 hours. The first time this happened I thought I had just gotten sick with something. But my MXE use pattern repeated a week later, and I got the exact same effects exactly five days after stopping use. Although I´ve never been through opiate withdrawal, the symptoms seemed similar.
Oh yeah, and I also got pretty serious acne on my forehead at this time, seemed like it must have been caused by the MXE.
That all happened about a year ago, and these days my health seems fine, no problems to speak of. Never had any bladder issues that I could detect.
So watch out with MXE, a very seductive substance... in the beginning it seems to have almost no downsides, but they manifest as use gets heavier. Watch out for the mania, it can really fuck you up. The drug has plenty of benefits, but it´s addictive and it can really warp you as well. Use with caution.