Try calm-aid and also try to get in to a sleep routine. I like to take my meds , eat , and take a calm -aid and watch a little tv then go to bed after my shift is over.

(continue)
This combination should give you confidence and help you to get to sleep.

Also, remember that some professionals and even celebrities are nervous when starting a presentation or show.

My apologies for repeating this so much: focus on the positive emotions and self-confidence and push aside the others.

My neurologist has me taking a little melatonin too. However, in order to get tired and fall asleep, you must first figure out what is the cause.

1. Pain or worry for a loved one

2. Insomnia has multiple causes
a. You have slept too much in a nap or drank too much coffee or the equivalent

b. This one is mine (and some friends of mine): I cannot honestly get tired too even to yawn because I cannot get my brain to stop thinking - working to solve a problem or problem, but I need to get my mind off of it to get that first yawn.

Solution: Try boring yourself by reading the most (in print) book that you have in your house.
NOTE: using any electronics is a mistake because it shines on your inner eye and makes most people more awake.

c. What personal problem that you have that you have no solution and thus cannot get it off your mind.

d. Fear because tomorrow you are about to make a major presentation for school that is important for the class or for work that might all about keeping and losing your job or a potential raise.

============================================================
As far as the fear, make sure to do practice of the presentation to make sure that you are comfortable, make sure you scan through the topic so that you can prepare yourself for the unexpected question (so you have some sort of answer to this question besides: Great question! I had not thought of that.

When giving the presentation it is all about whether it involves props or a slides on display, because this allows you to take eye contact off your audience.
However, during the presentation, you want to scan your co-workers and at time s talk if you are especially here talking to your boss alone.

(continue)

Thanks heaps for these answers, they look really helpful and I'll have a try out when I next feel worried 😊
I hope things go well for you too