I've never experienced this, but I've heard about it.

It is said that our mood and emotions are affected by the chemicals (neurotransmitters) in our brains. Too high of one chemical can cause people to feel 'low', while having too much of another chemical can cause people to feel 'high'. People with depression often have a constant surplus of one chemical which leads to the constant low mood. People with bipolar one the other hand, have chemical fluctuations which causes them to experience swinging between high and low moods.

I'm not sure if any of this information is accurate, but perhaps you're just experiencing a chemical fluctuation in your brain?

Whatever the case, enjoy that awesome good feeling while you can! And hopefully, it'll last