Dreams dictionary: Single

Dreams dictionary: Interpretation 1
If you are not single, but dream that you are, then it suggests that you need to stand up for yourself. You need to approach a situation or matter on your own instead of leaning on others. Be strong. Alternatively, the dream may be a metaphor that you are being "singled" out or being picked on.
Dreams dictionary: Miller Dream Interpretation
For married persons to dream that they are single, foretells that their union will not be harmonious, and constant despondency will confront them.