Have you had a practice run? Before doing it for real I strongly suggest doing a dummy run on a none work day, maybe when traffic is a bit lighter, just so you can familiarise yourself with the route and junction layouts etc. Knowing in advance where you are going and which lane you need to be in can remove a lot of potential stress once the traffic levels increase.
Also, make sure you prepare everything the night before. Check your bike over and pack your bag as much as you can. Trying to faff about in the morning when you need to get out of the door is a real pain in the Arris! If you prepare the night before then you can simply get up, enjoy your coffee then go, simples... 👍
Final thing, how used to cycling on the roads are you? This will make a big difference to how calm your journey is. If you have only recently started cycling then the traffic and roads may be a bit if a shock to you. If you are an experienced road cyclist but just never bothered commuting by bike then it probably won't be such a shock.