Petrified of driving!!

So I passed my driving test last year (I'm from the uk) drove my boyfriends car a few times then just stopped because I couldn't get the hang of his car. It was way too big and powerful for me. Anyway, I've only recently bought my own car and I'm so scared of driving it!! I really really want to get out in it but when I think 'right I'm going for it' my anxiety hits the roof and I back out. Any words of encouragement will be much appreciated