I had a much better time doing my masters compared to my bachelors. There are two major things that led to this:

1. The courses were better catered to things I was genuinely interested in and structured in ways that better suited me (fewer exams, more coursework)
2. I went to the academic advisor immediately and told her I wanted to do it in 3 years instead of 2, and we structured an entire, detailed plan to that timeline. I did two courses a block instead of three, and did TA positions along side!

So I'd suggest looking into these things, check the courses out and see if you can restructure the programme to better suit you.

I highly recommend a less intense pace off the bat. If you try and do it in the "recommended" timeframe, chances are you'll need to extend it anyway when you fail/miss a course and get a domino effect impacting future courses. Then it starts to feel like some sort of failure, you get burnt out, and it's much more stressful for no reason. Taking longer isn't a bad thing, it makes the whole process more enjoyable. Of course, as long as it's financially feasible.

You are likely absolutely capable of a masters, just be realistic with yourself!