If it was a keylogger it was most likely on your computer WELL before you updated Carbonite.
It can take at least a month or two after the keylogger (and the person reading the logs) gets and uses any info they obtain. They typically wait a while to hack your account to throw you off.
I HIGHLY suggest scanning computer for a virus. Chances are you are infected with something.
Run a FULL anti-virus scan. Hit every file on every drive .. not just the "suggested" files your AV program selects .. do a complete FULL scan.
Run a malware program. Programs like
Malwarebytes and
Ad-Aware are not only great ways to protect yourself but are also FREE to use. Again do FULL scans.
Make sure all AV programs as well as Malware programs are up to date. My AV updates daily.
Firewall running?? Make sure it is. This too can help protect you. I use McAfee AV (I know not the best but it is FREE with my Comcast account). It has a firewall. I set the Firewall security up so it warns me EVERYTIME a program tries to use the internet and I can choose to let it through or block it.
Nothing can protect you 100% short of disconnecting from the internet permanently (even then a friends USB thumb drive can still get you).