I know it is not even 2 hour since my last post, but I need to tell you:
I left my appartment at about 8am today and went running in the park!

For the first time in 8 or 9 years.
I was out for 30min but only ran for about 20min of those. (instead of running for 30min as I had planned). I had to stop because my legs were heavy and I had gotten a headache (mostly forehead) and my ears sort of hurt. Although it was not cold. Maybe my heartrate was to high? (I don't have anything to measure this)
Maybe it had to do with my eating too little yesterday. I only had vegetable in the evening. (overhours, tired and in a low mood. I wasn't hungry and didn't feel like eating. But did some exercise anyway.)
I ate a Banana and drank a glass of water before leaving for the park.
At least I did not get dizzy as I used to all these years ago. Maybe a little light-headed when I was back home.