Hi! Welcome to anxietyzone!
First, this is easier said than done but you need to take a deep breath and calm down. Think and try and rationalise your thoughts. None of us here are doctors - so none of us can diagnose you or evaluate your symptoms professionally. So if you are really concerned, seek medical advice.
However, your symptoms can all be anxiety related. The chances are that they most likely are. We have all been there. I have headaches which usually last for a week at a time. I also have visual disturbances - everything from floaters to flashers and from cloudy to tunnel vision. I have come to learn it is all anxiety.
Headaches from tumours don't come and go (for a start). If and when you don't think about it, and temporarily the headaches go, this for me screams anxiety. This is actually how I have been able to learn that my symptoms are anxiety related. I have been able to go from having severe chest pain with severe heart burn to no pain whatsoever in less than 10 minutes. Anxiety related symptoms can quickly spiral out of control - but as quickly as you can get into a vicious circle, you can get yourself out of one.
You said your headaches mainly come at night (same with me); headaches from tumours usually get worse with any activity that increases tension within the skull (bending over, lying down, sneezing, straining etc.) and is not in any way related to the time and day. Anxiety however, is. You can ask anyone here if their symptoms are worse at night and a lot will tell you that they are. This is certainly the case for me. And yes, it is the same for the morning. Mornings and nights are the worse.
You already know you have anxiety - you have also been told by a professional that you have anxiety. Therefore, we can safely conclude that you will inevitably get anxiety symptoms. All the symptoms you described are all related to anxiety - therefore you can conclude that the symptoms you are experiencing are very likely due to anxiety and not a brain tumour.
But like I said, we are not doctors.