For a change, why not you practice a different kind of meditation? The maithri bhavana (loving kindness meditation) is the most important. It is not easy for everyone to properly do Anapanasati because many other obstacles different to what you have experienced come up - if not now, then in the time to come. So why not make a change in practicing Asubha Bhavana (Meditation on Loathsomeness) and Dhathu/indriya Bhavana (Analysis of Four Elements).
Please keep in mind that you should not mix one meditation with another. You should get out of one type of meditation to get into another. Always before starting to meditate, spend a minute in being aware of your surrounding. Then always without fail start doing these two steps. First – before start of a meditation, say to self (Vitakka) that you are about to leave ‘normal’ self, and entering into a meditative state. Next – after each type of meditation - say to self (Vitakka) that you are about to leave ‘the meditative state’ to that of the day to day. As you start going into Jhana/Dyana states this practice will safeguard you.
Anytime when there is wandering thought, the concentration is not there. The appearing of a nimitta is a sign of concentration. When you develop an anapanasati nimitta, and practice it further, then you need a good knowledge of teachings (suttas) for you to overcome obstacles that you face. That is why in an earlier post – last week – I said that there is many a untruth in English Text on Dhamma - On Meditation specially. Nowhere in the Doctrine (Sutta) it is mentioned that one becomes a stream entrant (Sotapanna) thru meditation. It is by listening to dhamma that a disciple of the Buddha gets rid of the first three samyojana. Only then will one come to the proper frame of mind to do Meditation the right way. If not, you fall into all the trappings that come in the way. These trappings are both of this world and that of the other. There are forces of the netherworld that are going to cross your path that only one who is firmly established in the Noble Eightfold Path can overcome. That is why I said that meditation comes only when one is ready to go beyond the stage of Sotapanna to help get rid of / cut through the other 7 samyojana. Also that is the very reason that I said that otherwise going 'nuts' is a possibility and not enlightenment.
As mentioned earlier, the appearing of a nimitta is a sign of concentration. the ‘nimitta’ is your main object of focus. If hatred forms in a mind as a result of a cause, then that is Patigha nimitta (an objective to hate) which is your focus. When this focus is powerful, there is no room for a second different object of focus to get in the way. One of the other many obstacles that you have not yet faced is that of distractions in the form of colours – bright or subdued- of white, red, yellow, orange, blue, etc. and get trapped in them. One quality that’s always appropriate in establishing mindfulness is being watchful or alert, while maintaining a detached presence with what is experienced. Without a proper knowledge of dhamma this in not possible. The Pali word for alertness is sampajañña. It doesn’t mean being choicelessly aware of the present, or comprehending the present. Sampajañña means being aware of what you’re doing in the movements of the body, the movements in the mind. This is why mindfulness and alertness should always be paired.