WordPress.com to Self Hosted Advice Needed

Hi,
I have a WordPress.com site but went self hosted with Site Ground at the weekend. What happens with regards to my site hosted by WordPress and the custom domain name I purchased and pay £22 for plus the WordPress premium I pay £85 for yearly?
Original site is http://theamychronicals.wordpress.com which was changed to custom domain of http://whatamydidnext.com
Should I cancel Premium subscription and keep the domain renewal?

Would appreciate some advice on how to deal with the switch and what I should do to (if anything) next.

Thank you in advance.

Amy