I try to keep the Son's day holy, that day decided upon by the first Christians as our day of observance. I attend Mass when I can, but also work on it to take care of my family - Jesus understands this completely.
Now, about keeping kosher. You know that eating those things that the old law says you can eat must be adhered to, but the food itself also has to be prepared correctly. You just cannot eat any ordinary chicken or piece of beef you buy from the grocery store or from a restaurant. It has to be slaughtered and prepared in the proper manner, otherwise the food is as unclean as the one's that are prohibited. So if you eat at Micky D's, or buy your meat and poultry like I do from the local Publix, Shop Rite, or Kroger's, you are sinning and for your sake I pray that is not the case.
I used to be catholic, i know how you feel.
As for the meat, you are correct that they must be killed correctly which is to drain their blood. Every packing plant I know of does this (i'm in agriculture). They use a captive bolt pistol to scramble the brain of the cow, then they hang it upside down, then they cut its jugular and drain it of blood. This is a kosher kill according to scripture because the blood has been removed.
So feel better about the beef and chicken you eat. Just don't feel good about the pork and shrimp