Get a good “dirk”.
5-6 inch blade is meant to be used up close, easy to shove up to the hilt with little effort and has an immediate effect on any attacker.
Also easy to conceal.
Be carefull with “dirks”. They are illegal to carry concealed in many jurisdictions and carry felony implications. Try not to carry anything you cannot explain away. A concealed5-6” fixed blade “dirk” or dagger is more potential trouble than a pistol.
As a bladed backup I like http://www.hideawayknife.com/main.php They are a bit pricey but almost impossible to dislodge from your grip,fast,concealable,cut like a larger knife and can be deployed and used in conjunction with a pistol. The size usually falls under legal maximums for concealed fixed blades. Sort of makes you a human “velociraptor”
Dirks are also illegal as heck in most states, I believe. Even with a CCW permit.
Does that make sense? Nope, but there it is...