Working full time but my DIY postbacc GPA is not off to a good start. Still keep going?

Hi all! Got a 3.85 GPA in Computer Science (BS, undergrad) but now am pivoting careers and trying to take some missing prerequisites. I did two classes last semester (gen bio II + phys I) and really struggled to keep up with working full time. I got a B in both (technically B+ but the community college doesn't do +/-). I took organic chemistry over the summer at my alma mater (4-year university) and am on track for a B in that as well. All three professors for these courses were very difficult in my opinion. Besides these three grades, there's only two other Bs on my transcript (no Cs). I still have biochemistry, organic chemistry II, and physics II to take. I am really disappointed with my performance these past 5 months but I have fought so hard to support myself and study. I understand that this "downward" trend in postbacc is not attractive to adcoms, but I also think that retaking these courses wouldn't be worth the squeeze. Obviously, the classes I have left to take are even harder, so this has been a hit to my confidence -- evidently I'll need some As somehow. Any advice for how to handle my upcoming classes? Should I be concerned with these three Bs? Are there any other courses/helpful prerequisites that might unironically be "easier" to get As in?