Let's start with the ones that are clearest in terms of their use among professionals in television.
Day player and co-star are the same in terms of the work that is done. The only difference is that one term (day player) is contractual, and the term co-star is a credit.
If you are hired on a TV show to speak a few lines (usually between 1 and 10), and perform in 1 or 2 scenes, your contract will be a day player contract, meaning you are paid by the day - usually the SAG-AFTRA scale, plus ten. Day players with several scenes in different locations, or over a number of days, will sometimes be given a weekly contract.
A guest star is usually on a weekly contract (they are paid a weekly salary) and their credit is at the "top of the show," meaning it's at the beginning of the show as opposed to a co-star which is at the end of the show. As you might guess, a guest star has a bigger role that is an integral part of the story line.
A recurring role can be a co-star or guest star who appears in more than one episode as the same character.
Regular recurring, and recurring regular are a little less well-defined, but here's my take on the terms.
Regular recurring is a co-star who shows up on a somewhat regular basis. They may be in episode 2, then in episodes 5, 9, and 13. (In a 13 episode cable series.) Often this actor is not "on contract," meaning they are not critical to the story and if not available they could be written out of that episode.
A recurring regular is a character who is more central to the on-going story. For example, he may be the owner of a soda shop where the characters hang out and there are scenes at the shop every 2 or 3 episodes. Maybe he gives a few words of advice to the other characters. This actor may be given a contract because the producers want to be sure that he is available whenever they need him.
Hope many of these roles are in your near future.