Obstacles to meditation are really from within. Environments are from within; you create your own environments. Try to be happy in whatever situation you are placed. Do not complain. Bear sufferings. You can conquer Nature. Maya (Delusion) is nothing but a small or non-entity for a Wise person.
The obstacles to meditation are only from within. Sleepiness, passions, confused state of the mind, fancies and wild imagination (building castles in the air) are the chief obstacles that stand in the way of fixing the mind on God or Soul. The five hindrances to meditation, viz., sense-desire, ill-will, sloth-torpor, flurry-worry and perplexity should be removed. For, when these are not removed, meditation cannot arise. The mind that lusts after many things through sense-desire is not concentrated on one object; or being overcome by sense-desire, it does not enter upon the progress of meditation in order to put away the sensuous element. The mind that is harassed by ill-will concerning an object does not proceed at once. The mind that is overcome by sloth and torpor is unwieldy. Obsessed by worry and flurry, it does not repose, but flirts about. Struck by perplexity, it does not go on the path that leads to the attainment of meditation and Samadhi. Obstacles to meditation are thus really from within. They are not from without. Train the mind properly. Sleep, tossing of mind from one object to another, memory of sensual pleasures and hidden subtle desires are four stumbling blocks in meditation.
Drowsiness and Wild Imagination
When the mind has been withdrawn from objects through Vairagya (dispassion) and withdrawal of senses, do not allow it to go into sleep or fancies and wild imagination. When you constantly contemplate on the meaning of the great words Aham Brahmasmi (I am Soul) or Tat Tvam Asi (You are That) through the process of this practice, all the Senses (seeing, hearing, touching, tasting and smelling) will stop. But, owing to the force of past Karmas, fancies and wild imagination (building castles in the air) will continue. Mind builds castles in the air. This is a serious obstacle to meditation. It should be stopped by Self-Inquiry. Sometimes, during the course of meditation, the mind suddenly slips into its old grooves for sleeping. People think that they are meditating, while they are actually sleeping. A mixture of drowsiness and wild imagination (building castles in the air, reverie) is mistaken by aspirants for deep meditation and Samadhi. The mind appears to be established in concentration and free from distraction. This is a mistake. Stupefaction arising from fear or wonder, mental restlessness and mental depression are other disturbing factors in meditation.
Closely watch the mind. Make it one-pointed and allow it to rest on the Soul, your true nature. Be thoughtful, careful and vigilant. Stand up for ten minutes and dash cold water on the face and head, if drowsiness comes in. Remove the two serious obstacles of drowsiness and wild imagination by Self-Inquiry, Pranayama and light, Sattvic diet. Find out the disturbing causes and remove them. Avoid the company of those whom your mind dislikes. Do not argue. Do not contradict. Do not try to convince persons who are unreasonable and undeveloped. Talk little. Observe Silence. Live alone. In this way, you can avoid all sorts of excitements. Have constant good company of wise person. Study elevating books and scriptures. Repeat OM with meaning and feeling. All depressing thoughts will melt away. If you are alert and if by protracted efforts and incessant, vigilant meditation on Soul, you get over the obstacles of sleep, wild imagination, etc., the steady wise thoughts and wisdom will dawn in no time. Ignorance will vanish. You will be established in thoughtless blissful state. All accumulated Karmas will be burnt up in the fire of wisdom.
Dreams in Meditation
Various sorts of fantastic dreams trouble some aspirants very much. Sometimes, there is a mixture of meditation and dreams. The presence of dreams denotes that you are not yet well-established in deep meditation, that you have not removed tossing of the mind and that you have not done constant, intense practice. As the phenomenon of dreams is very peculiar and inexplicable, it is very difficult to control dreams unless you wipe out all the Impression in the causal body and control all thoughts. As you grow in purity, Viveka and concentration, dreams will decrease.
Mind – Its Mysteries and Control by Sri Swami Sivananda