I hosted my own shard and friends can come play on it perfectly but when I try to connect to my own client i freeze every 2 steps ingame and experience slow play.

( I'm behind a router but i opened ports 5000-5004 )

If you are trying to run the client on the same machine as the server then I could see this happening. It really depends on the hardware you have, your connection speed to your own network and your bandwidth.