There is a part of the nature which I have called the vital mind; the function of this mind is not to think and reason, to perceive, consider and find out or value things, for that is the function of the thinking mind proper, buddhi, — but to plan or dream or imagine what can be done. It makes formations for the future which the will can try to carry out if opportunity and circumstances become favourable or even it can work to make them favourable. In men of action this faculty is prominent and a leader of their nature; great men of action always have it in a very high measure. But even if one is not a man of action or practical realisation or if circumstances are not favourable or one can do only small and ordinary things, this vital mind is there. It acts on them on a small scale, or if it needs some sense of largeness, what it does very often is to plan in the void, knowing that it cannot realise its plans or else to imagine big things, stories, adventures, great doing in which oneself is the hero or the creator. What you describe as happening in you is the rush of this vital mind or imagination making its formations; its action is not peculiar to you but works pretty much in the same way in most people — but in each according to his turn of fancy, interest, favourite ideas and desire.
Vital mind is a mind of dynamic will, action, desire - occupied with force and achievement and satisfaction and possession, enjoyment and suffering, giving and taking, growth, expansion, success and failure, good fortune and ill fortune, etc. Day-dreaming, talking mentally to another person — are the actions of vital mind.
It is undesirable to make peace, joy or Ananda a condition for following the Yoga. If you do so, then the vital, not the psychic, takes the lead. When the vital takes the lead, then unrest, despondency, unhappiness can always come, since these things are the very nature of the vital — the vital can never remain constantly in joy and peace, for it needs their opposites in order to have the sense of the drama of life.
It is quite possible and even usual during a time shorter or longer, sometimes very long, for the mind to accept the Divine or the yogic ideal while the vital is unconvinced and unsurrendered and goes obstinately on its way of desire, passion and attraction to the ordinary life. Their division or their conflict is the cause of most of the more acute difficulties of the sadhana.
O man, the events that meet thee on thy road,
Though they smite the body and soul with joy and grief,
Are not thy fate; they touch thee awhile and pass;
Even death can cut not short thy spirit's walk:
Thy goal, the road thou choosest are thy fate.