From my experience it is most likely a nimitta. Nimittas are mental objects that are actually reflections of one's mind. In Buddhism we use them in Samatha meditation. One builds up one's concentration and positive emotions to get beautiful nimitta. They can be so beautiful it draws one into a single pointed concentration. This is Samadhi or Jnana. In this state all negative emotions are gone and only good ones arise. There are many different levels of absorption, though the first one is usually misinterpreted as, "Union with God" - it's that blissful. In Buddhism jnana is a part of the 8 fold path (aka right concentration). So if done the other 7 aspects one can reach enlightenment. Although Buddhists wish to renounce (to the point of no attachment)sensory pleasures, Jnana is all good because it does not derive it's bliss from the five senses. Furthermore Jnana helps renounce said sensory pleasures, because it is so much better.
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