Torrent behind proxies

Hi there my details are

Bitcommet x64 1.34 Stable Release
Windows 8 x64
Windows firewall
Connection behind routers
yellow light:

• UDP opened
  
• TCP blocked (idk why it's blocked, it's opened in win firewall)
  
• upnp added

Okay, my torrent were stable at high speed since 3 days ago
the problem is that my speed is unstable until now, as I traced it out, I found that peers connected to me only last about 1 minute
can anyone figure this out?

I have 4Mb connection to my country connection, 384kbps global connection
Proxy is used to trick it out, so I can download globaly with 4Mb connection
I used proxy since last month, but 3 days ago seems the problem arise
changes the proxy don't help at all
as I learn about bitcomet's setting, I found option about "don't use proxy for tracker/p2p connection"
which should I enable, please explain?
I needn't to be anonymous, my concern is speed for DL/UL


My speed goes 4Mb for 1 minute then it would go down to 60kB/s, then go down again to 10kB/s, sometimes it goes up to 100kB/s
10 tasks running at the same time, so I thought the overall speed won't less than 200kB/s
average speed DL/UL last week is about 400kB/s for download and 300kB/s for upload at the same time
right now, even the UL can't reach more than 100kB/s