Feeling intense DP. Please give me some advice.

Note: This post might be depressing so those who are sensitive (or people new to this forum) may want to skip it.

I am a long term sufferer of depersonalization (since 2005). I recently understood I have autism as well.
My DP started when I was in school. I assume it was because I was trying very hard to adapt to that environment and act like everyone else.

I experienced a decline in my social skills recently. This is sometimes called an autistic burnout.

This decline generates a lot of fear. The fear my autism will be more visible to people than before.

And that people won't take me seriously anymore.

This fear and anxiety makes me feel like I don't know what I am anymore. I feel like I am close to having a nervous breakdown.

I feel like I don't have the strength to pretend that I don't have a mental illness.

I want to breakdown and cry in front of everyone and beg them to help me.

It's kind of like I'm losing my connection to other people and the world...and like they don't exist...and I don't exist.

This feeling is worst after dark.

The consequence of feeling this way is I feel more depressed and I have even less motivation than before to talk and engage with people.

I think my derealization has become worse. Because I feel more out-of-sync with the world.
Depersonalization is also the worst I've known. I kind of feel like I'm not attached to my physical body.

Since it's more practical to go on like before I will do that. But I hope this dreadful feeling will pass soon and I will feel more stable.

Has anyone experienced intense periods of DP/DR like this (doesn't have to be related to autism)? How long do they last?