aMule is known to be one of the fastests (if not the fastest) ed2k clients. So no problem on that side.
Now, if you go removing the ~/.aMule directory, you will be always loosoing the credits other ppl have on you, nd so, they will be ore time in queue and less time downloading, ou will win less credits on them and have less download.
Stay calm, give some days untill you have enough credits on other ppl's clients and then, downloading speed will begin to be great.
Read
http://www.amule.org/wiki/index.php/FAQ_eD2k/Kademlia to know what credits are if you don't know already.
Again, wait some days, maybe a couple of weeks. Download speed is slow first days, then it boosts up.
Greetings!