Chances are that you have not. Part of the problem with tools like rkhunter and etherape is that they give a lot of false warnings, as does any IDS software. You need to review the man pages and understand what the tools are doing and then evaluate the warnings you receive on a case-by-case basis. You mention SSHD, do you use password authentication? Do you allow root passwords? Do you have it restricted at all via IPtables. Do you run any other server processes? Do you examine your logs routinely? Do you use a program like fail2ban to help counteract brute force password attempts?
If you think you may have been compromised, then you will want to perform an investigation. Start by removing the network cable or putting a firewall up in front of the machine. Then review the CERT intruder detection check list for things to look for. Here is a link
Next examine the output netstat -pane, lsof -pwn, ps -afwwwe. Look for any files with the setuid and guid bits set. If you need help analyzing these files, please post the output as an attachment or let one of use know and we will help arrange for a location to post them.