Hi @Lise07, welcome to the forum.
I'm not a mental health professional, nor an expert, but have had personal experience of being treated for mental illness for about 30 years. This has involved many first hand experiences with different medications, as well as the symptoms of changing from one to another, or discontinuing altogether.
It seems to me that what you are describing might possibly be, as you suspect, side effects of discontinuing your medication. In that case, the symptoms may ease as your body becomes more accustomed to being without the meds. One to two months seems a reasonably long amount of time to have been tapering down though, so it may be a bit unusual that you are still experiencing significant side effects of this process. For me, the effects of discontinuation have usually passed more quickly than what you have described.
On the other hand, it seems possible that what you are experiencing is a return of the actual symptoms of your mental ill health, which may stick around, or even get worse, as they are no longer being treated or managed by medication. I wonder who prescribed the meds for you in the first place, and whether you have discussed with them this current decision to wean off. It would seem wise to do that, if possible.
My experience suggests that a psychologist may not necessarily be the best person to be advising you to cease taking medication. In my experience, it is a psychiatrist, or at least a trusted GP, who will have the best advice on medications, as they specialise more in medical treatment of mental illness.
It sounds like the GP you saw was not your regular GP? Or maybe you don't have a regular GP. If not, I'd suggest it might be helpful to develop an ongoing relation with one who has a good understanding of mental health issues. It's been so very valuable to me that my GP knows and understands my mental health issues over time, and is thus better able to consider all that might be involved, and better advise me.
Just because you were doing well on your meds doesn't necessarily mean that your medication should be discontinued. In many instances a relapse may occur if medication is ceased. The fact that you were doing well may be partly due to you taking the medication in the first place, so that ceasing it may be causing a return of original symptoms.
So, it seems to me that what you are experiencing could be either an effect of discontinuation, or an actual flare up of mental illness symptoms, due to it no longer being treated with medication.
In my case, decisions about medications for my condition are made only in consultation with my psychiatrist. A psychiatrist is the medical expert on medications. In my experience, a psychologist will be an expert in 'talk therapy', but not so much on questions of medication.
Just to emphasise again that I am no expert, except in my own personal experience. I hope what I have written may be of some use to you. I'd probably be seeing a medical doctor again about what you are going through, and, depending on what your mental health diagnosis is, perhaps preferably a psychiatrist.