You may recall that humoural theory is based on the ancient and medieval physiology and medicine as expounded by Empedocles, Hippocrates, and Galen – it’s all to do with the four blocks or ‘roots’ of the material world that manifest in certain humours and their related temperaments. It’s not so much that the humour (in this bace Phlegm) causes the related temperament (in this case, Phlegmatic), but more that it in some way resides in it – pervading the whole of the surrounding energy – invading the whole of your perceived day.
Often we experience various combinations of the four humours resulting in mixed temperaments – the more balanced between the four humours – the better and so when we experience a humour/temperament in its pure form, it feels uncomfortably ‘out of control’.
The phlegmatic energy is, as you might expect with the Sun and Moon both in watery signs, wet and perhaps a bit dreary. This is because it is connected with the Jungian Function of ‘feeling’ and that suggests not only getting bogged down in your feelings but also your inability to access the opposite Jungian Function of ‘thinking’ and hence hence rationalise it all away.
Best advice when dealing with such energy is for the moment to take pesky feelings with a grain of salt – acknowledge them – and then pack them away until you feel more able to deal with them in a couple of days. There probably isn’t much you could do about them anyway because chances are, at the moment you’re feeling a bit dull in the sense of being ‘under the weather’.