Emsie, if your periods are that short it is unlikely you're ovulating. Get a copy of Lara Briden's 'Hormone Repair Manual' for the over 40s - it will explain more. If your cycle is that short it is more likely an anovulatory bleed, not a true period with the shedding of an egg after ovulation and a corpus luteum producing progesterone.
You might want to supplement with body identical utrogestan progesterone in the luteal phase - after when you would usually have ovulated. Because if you don't ovulate, you don't produce progesterone of your own - which is what leads to many peri symptoms.... Lara Briden recommends using utrogestan first, before considering estrogen.
Low progesterone is also what causes the symptoms you're describing there...
