My iPhone is not functioning properly after update.

I recently updated my phone to the newest iOS update.

Now all of a sudden if it is not on charge the screen just remains black completely.

If it is connected to a source of power, it's charger it just keep flashing

By this I mean the Apple logo appears for around a particular amount of time, only then to disappear to a black screen for maybe three-to-five odd seconds and repeat itself once again( I've looked on videos to see the apple logo stay on others, unlike mine flashes).

My iPhone is a five, I live in the UK, I cannot go to apple until later so I'd prefer to get this fixed instantly.

If anyone has a good way to solve this please comment and explain in understandable fluent English as I need this solved ASAP.