If timing around random irl happenings of any sort is an issue, it's best to play late evenings. Do all chores that you're expected to pitch in for FIRST. Ask all in the house if they expect they'll need anything before you shower, etc. She'll likely not be going to Wal-Mart to shop at this point. When things settle down in the day is realistically the only time of day you ought to be trying to play a full game. If she leaves for groceries, don't queue up. Starting a queue can take 15 min or more when you combine, queue times, bans, picks, very possible dodges riiiiiight before loading screen, wash, rinse repeat. Then there's someone's toaster keeping you in loading screen. Then your game is 20 mins in and your mom comes back and wants help because she's somehow managed to buy half the freaking store and shove it in her trunk in the space of 40 mins.
So yeah.... Just don't do it during the day. Do an Aram or something.
As for the jobs, mayyyybe give them a couple days and call them. Have an intelligent question or two ready about the job they're offering (to show them you at least know enough to know what questions to ask). Start googling stuff on making yourself stand out in a good way during job hunts.
Also, if your mom is chillaxing during a favorite couple of episodes of HER favorite show, ask her if she expects to need help during it. It would be a good time to let her know you'll play a game during HER entertainment time. That might let her see that chill time is chill time, no matter what form it takes (hopefully she's self-aware enough to feel like a hypocrite if she allows it for herself but pitches a fit about others). If she has too much of a double standard.... maybe start vacuuming the living room during her show. :P