Take it slow. Rome wasn't built in a day.
Draw little things, maybe a small cartoon rabbit. It may not be what you want to draw, but you need to build up the confidence to actually sit down and do it first. Drawing is a hard hobby and I am by no means an expert, but when my art gets overwhelming I like to step back, do something else and then come back to it in an hour or so when I've had time to calm down.
Getting overwhelmed with things is frustrating and can throw you off, but just pause, take a deep breath, go watch YouTube for a while and come back and try again. Don't give up so easily, but remember to be gentle with yourself :))