I'm sorry you're struggling so much.
While nothing in your post points to specific symptoms of either (and I'm sure some will roll their eyes at me), I wonder if you've considered the possibility of being neurodiverse? ASD or ADHD...I ask because in recent years its been recognised that many women have gone undiagnosed for either as both conditions present differently in women than men.
Lots of women are now finally being diagnosed in their 30s, 40s and 50s and its common for them to have struggled with illnesses such as depression. (I'm one of them.) With ADHD also (not sure about ASD) it often doesn't start to become noticeable in girls until aprx the age of 12.
I also strongly recommend a blood test to check your iron, b12, thyroid and especially vitamin d.
I know it probably sounds like me telling an insomniac to avoid caffeine in the evenings but as someone who's also lived/living with chronic and treatment resistent depression, i know that when my levels of these are low (even if still above the nhs deficiency threshold) it really makes my depression worse. And being still a year post partum, with 3 small children, I wouldn't be surprised if your stores weren't depleted.
I'm assuming you have with the treatment you've tried in the past, but are you under the care of - or have you been seen by - a psychiatrist? It would be worth considering a referral if not, as they can prescribe / advise on medications where GPs can't (just as any consultant would).
I'm making no assumptions about your financial situation, so if you're in a position to afford private blood tests then look into it. Also, if you can, I would throw money at making your daily life as easy as possible to lift the burden of household and even childcare from you so that you can focus on looking after yourself more. Even if this just means more rest.
If there is nothing underlying that could be making it worse, like I've suggested, then I also wouldn't be surprised if its just that you're going through a difficult few years. Motherhood with small children tips women with otherwise robust mental health to the edge. When your mental health is already fragile, it's no wonder you're struggling more. (Which is another reason I think throw money at daily life if you can. )
On top of which, you've dealt with significant trauma that's resulted in ptsd. Even if your treatment for it was successful, it takes time to convalesce.
It really does take time and rest to recover from trauma to mental health and we often don't allow for this. I can't say that you'll cure depression completely, but I do think it can get better for you.
Don't lose hope just yet op. 💐