Strange bandwidth of steemit

I don't really understand how the steemit bandwidth changed today.

In the morning, I wanted to post a picture, and the system told me that " bandwidth limit exceeded. Please wait to transact or power up STEEM."

So I checked steemd.com and found out that my Bandwidth remaining was negative like -34%, and the Bandwidth allowance was extremely low closing to 100kb. In the meantime, my reputation jumped from 25 to 31 then to 32 then quickly reached 34.

According to the definition of reputation, for example of many articles, from 25-34 is like to jump 10^9 times. How can that be I really don't understand.

Anyway, as I could not post anything with a negetive bandwidth, I went out to enjoy my Sunday. When I came back, I checked steemd.com/@causenet again, and I saw this:

Oh, my bandwidth becomes over 20Mb, which is nice and I still don't understand what happened today.

Anyone please explain how all those things happen? As a little fish and new to steemit, I want to know the reason so I can understand steemit better.

PS: after posted this one, I checked again and got:

So I used 1k bandwidth, but the allowreance droped from 20Mb to 4.4Mb, and reputation rised 0.1. Woooooo!