Hi there and thanks so much for posting this question. There are many reasons i may say that the biological explanation is that there is an neurochemistry imbalance in the brain that tends to take neurotransmitters into a roller coaster. Normally is dopamine, serotonin and adrenalin the neurotransmitters that ten to behave more up and down. My suggestion is to use meditation and exercise techniques that will help you feel not in both extremes but more controlled. It is true that if you are mentioning it is because you are feeling it and we need an action plan for it. Add daily exercises in the morning and at night and monitor if symptoms improve.
thanks so much and I hope this was helpful