Anyone know what causes regular miserable mood

[ALiceM20]

So a bit of background Since probably somewhere mid through teenager years I was going regularly through good mood for few days to sometimes weeks (sometimes happy and super excited and sometimes ok neutral) and then its like id always hit a what seems like a crash and go for days or weeks just feeling really miserable and exhausted to the point where i literally don't wanna do anything coz it seems like too much effort and i just feel so low like nothing makes me happy or excited. They feel like very big swings, during teenager years i thought it wad just normal teenager moods and growing up then in uni and for couple of years after was difficult times so didnt think too much of it but now going through another really miserable period of time im wondering what could be causing it? or is it just normal to have very happy periods and very low periods regularly?

You could keep a mood diary to monitor if there is a sequence of events/a person or a pattern which is causing your mood to change. Are you eating regularly? I get very Hangry (hunger makes me angry). You could use a hobby/activity as a type of distraction.

For me it's irrational, negative, intensely self-critical thoughts that give me low moods. I wasn't even aware of this being the cause for nearly 20 years.

Do you have a long period of happiness (as in months) followed by long period of constant low mood? I'm not an expert but this could be different to regular depression.. could be bipolar disorder, where you need medication, though CBT can be of some help.

Reading your post again you say mood changes are over days/weeks so sounds more like regular depression (again no expert, just going on my personal experience).
For me I use self help CBT ( I've posted about this today in other threads in this section).
I don't realise I've been thinking a very negative thought, I just lose interest in doing stuff & feel low. Once I recognize the negative thinking that caused the low mood & deal with it I feel better again.

Thank you both
I eat regularly and as far as i can see there is no real reason for my mood changes, just happens out of nowhere sometimes.
@Gourmetgold what's your threat name?
I think maybe i should go speak to my gp about it see what they say. Ive been doing self help cpurses on positive thinking and dojng affirmations/journaling yet my mood still seems to come sometimes out of nowhere

Here's the thread:
expert advice.

What made you a) think you might have depression and b) do something about it?

It wasn't started by me, but I posted about the CBT self-help I do on the thread.

The books author David Burns has some good YouTube videos, especially an interview by the 'davidlarocheworld' channel.

Don't know where 'expert advice' came from!...the thread is in current 'mental health' threads at the moment