That's a wonderful experience to share with. Was it the first time you did meditation? I haven't heard about Zazen Session.. mind to introduce a bit about it? =)
Zazen is a zen buddhism meditation. Zazen means sitting. You just sit and let your mind rest in its own natural state. No visualization or anything. There should be no goal of the meditation, the only goal is sitting

. The result is a clear and calm mind which I need the most atm. It's important to know when you have toughts to just cast them out and come back to your natural state.
If you do this meditation right you will have a calm mind and be able to live more in the "NOW", I am no expert however but for me it works. Somethimes I get in a sort of free floating state of conciousness for a short period of time
I guess if you are a bit stressed it might be usefull to use this meditation before you want to visualize. I usually do it for about 20 min.