I was able to look up my pelvic ultrasound results online today. I haven't seen my doctor yet but I'm as capable as reading the report, finding definitions for the terms, and then searching the internet for things to alarm me as anyone.
Turns out I have a small submucosal echogenic nodule which suggests adenomyosis (directly from the report). This means some of the lining of my uterus has grown into the muscular wall, causing heavy and irregular periods and the between-period bleeding. It is not a dangerous condition but in some people can be extremely painful, to the extent that you feel like you are in the last stages of giving birth. There are some treatments (mainly to control the pain) but the only cure is a hysterectomy. The causes are unclear, but may be related to too much estrogen or trauma (like during pregnancy or a C-section). It is most common in women of my age - between child bearing and menopause. It generally goes away when you hit menopause.
Since I only have a small nodule and annoying symptoms but very little pain, I am not planning to have a hysterectomy. One thing I have had trouble finding on the internet is the progression (if any) of the condition. Will the nodule stay small, or will it grow and get worse? Over the last couple of years I've gone from light spotting between periods to quite prolonged and heavy flow, so that would indicate it is gradually getting worse.
Things I have been attributing to possible peri-menopause and/or just being overweight and unhealthy may have been influenced by this. Feeling run down, depressed, fuzzy brain, PMS, night sweats, clots and my uneven periods even though I am on the pill (sorry if that is TMI, but if you've read this far you're not too squeamish). It can also cause migraines, enlarged uterus (which I don't have), really bad cramps, and rapid weight gain, among other things.
Recommendations include eating mainly unprocessed food, getting enough sleep, hormone-balancing drugs and anti-inflammitories.
Obviously I need to talk to my doctor soon.