Don't get frustrated with me please because I'm no mechanic and I'm just a chick who has no one else who can currently look at it for me.and can't really afford to take it to the shop. I may not know what you're talking, about or vice versa, but I'll do my best.

I have an 04 honda accord, six speed manual transmission, v6 that is suddenly acting up and not running properly.
I already replaced the upstream and couldn't afford to get the downstream 02 sensor yet.
the code reader said one was stuck open or something..because it had been running terrible and idle was pathetic. The check engine light has been blinking and not solid but it didnt seem to really be doing much other than idling weird & using lots of gas. I smell more exhaust than I used to. First codes that came up when I First had it checked, . Like 12 came up. Some 2xs one only one time no idea what that is all about. But some guy said he thought was indicating that my upstream sensor was stuck open.as per mechanic who did the test on the codes anyway.
After changing the 02 upstream sensor and resetting the codes the car seemed to idle a lot better but it didn't do much for the power loss at low rpm (1st &2nd gear) and the light backfire not loud . So I checked codes again and now it's throwing 15 codes and I'm just super frustrated.
All the codes come up saying that I had misfire on all cylinders. I am not sure what it's supposed to mean when you disconnect each spark plug one at a time and no noticeable change occurs..do you think this could be due to not having changed out both sensors or maybe an injector? Could it be something electrical (my interior lights seem to be dim, my air conditioner stopped working but heater is good. I was wondering If this could have been something to do with my stereo system and maybe somewhere along the way shorting out or not grounded right, it was already in when I got the car and sounds great but my touch screen deck has Hella heat coming out from behind it. I know I know. I need some guy to check all this stuff out in person but sadly my older kids dad died and he was probably the person to do that. My youngest one's dad is not really confident in it since he is not necessarily mechanically inclined. I feel like my life is exhausting sorry. ​​​any advice or things I should be trying to look at or check would be greatly appreciated and very helpful. Honestly
I don't think it's the plugs or coils. I know I sound dumb. I have never had any experience with this at all