What you're describing is par for the course with BPD/EUPD which ever title you prefer, I'm more used to BPD.
Some p/docs like to categorise BPD depression, therefore some get a dx of dysthymia, rather than clinical depression although it can develop into a more serious clinical depression.
Sounds like you're very flat. How are you managing with self care & daily functioning? If you're not managing to care for yourself on a basic level you need to speak to a MH support worker if you have one.
The paranoia is usually induced by stress, when life is less favourable, or when one is experiencing prolonged stressors, mistrust issues etc.... I experience the dreadful paranoia when I my mood is low too or if I am subjected to chronic stressors. I guess the severe anxiety & paranoia is a result of past hurt/trauma. May be a symptom of PTSD & mistrust.
My lows can last for months, although I cover it up now because I do not have a MH care team at present. I have been hospitalised because my lows were so bad in the past as I experience suicidal thoughts.
It may help to try identify if there is cause/trigger to your depression if that is at all possible. Have you ever done any CBT or therapy?