Software Developer with ADHD

Working as full stack intern was super difficult for me. Because when some task was assigned to me I wasn't sure if I can do that or not, if I can finish it in time or not. There was constant panic attack. I often set the bar so high that I can't achieve. And it ruined my sleep, my diet. Now i am joining new company. I just don't want to go through that horrible process again. Anybody experienced something like this? Thankful for any advice.