Next time try the same flow but without as much effort and you'll notice a totally different aspect of your practice. Even though we all know you can't logically rest anything whilst straining it the moment people get onto a mat they think everything must look "perfect" (even though they can't see themselves, only other people) and that is the opposite of the whole point as its way more about feeling from inside than shaping from the outside.
A lot of instructors don't even know this and thus can't teach it because the cultural appropriation is strong and many just bobbed their head to the beat without peeping the lyrics. In a nutshell, the slower you go the quicker you get there and that is the exact antithesis of the modern world.
The reason why I advise classes is because you can easily slide into bad habits/poor form before you develop the proprioceptive awareness and this compounds like when you see someone with hunched over posture - that feels straight to them. If you align their spine correctly they'll say they feel like they're leaning back. Also the practice naturally improves your immune system, stress response etc... so stick with it, don't worry and be happy.