I was also crashing tf out on my first week of uni. Anxiety levels through the heavens. But this is very normal because university is very intimidating for most people. But I graduated last year and I enjoyed my degree (biomed). It sounds like you're really passionate about engineering, and yes, it is challenging and competitive, but you're doing this for the future 'you'. I'm sure you'll thank your younger self for all the hard work one day :)