@Mimi, yes I can have this same problem before a run or during. That's why I try to wait to very late morning to run to ensure that I'm "running on empty" For me this is strictly a morning issue. It varies also. Today I have had my typical 2 cups of coffee with no problems. I'm actually also sort of "revved up" because I've got an atypical day with lots of running around & errands. So I like how one poster called it the "dreads" as emotion can definitely affect it, although with me seems to be unpredictable. Because it's only in the morning for me I think it is influenced by what I eat the night before AND the caffeine in the morning. Seems to be the combination. Then when you add on emotional stress or whatever it can trigger.
Happy riding.