Should I resign from my first job or am I overreacting?

I’m a new-ish lab tech working pathology and I’m seriously considering resigning. I’d really appreciate advice from people who have worked in healthcare/labs.
I’ve been struggling with the workplace for months. I’m slower than some of the experienced staff and I know I still have things to improve, but I feel like two particular senior staff are consistently condescending toward me and I’m increasingly feeling humiliated rather than trained.
There have also been several situations where I was blamed/corrected for things that I genuinely don’t think were my fault. Some were things I had never been properly shown, some were based on assumptions about what I’d done, and sometimes I was simply following what was written on the specimen/request.

I also feel like I’m treated differently from certain other staff. One coworker in particular can be quite rude/condescending toward me, while the supervisor seems to constantly back her up.
Today was basically the final straw. I finished my assigned work and asked if there were more to do I was told no, despite there visibly being more work
I was dismissed and told to go do something else.

I’m exhausted and honestly want to call in sick for the rest of this week and resign on Monday. BUT I don’t want to screw myself over professionally, especially because this is my first proper job and I may need references.

So what would you do?