Hello and wlecome. This is a question that comes up often and one I have experienced myself when my anxiety is peaking. I have actually woke up in the morning and been overwhelmed with feelings of anxiety. I have bursts into tears and felt like I would never be able to make it through the day.
I still have this happen occasionally but I do take medication which has helped me as well as therapy. SC explained the cause of this phenomon very well. A big part is also the way you talk yourself through the feelings. I noticed that I was more negative during my anxiety spells and could even talk myself into having a panic attack. If I slow my breathing down and tell myself it will pass, I usually feel better.
Like you, as the day gets longer I start to feel better and by evening I feel good but I think that is because I am glad I made it through another day :)
I am glad you found this great forum and I look forward to getting to know you better.
Kindly,
Kitt