Website Tune up and Security contact form fixing Wordpress Website

Hi,

I have the website www.balloonbysteph.co.uk and i have some issues that need resolving in order for it to be a fully functioning website once again.

Firstly i recently logged in to find that all my plugins had disapeared, i dont know wether this is a hack or not if you search for installed plugins they are there but they are not showing in the dashboard, so i cannot update and add new photos to my various galleries, update my easingslider or update my seo or contact form 7.

i can probally give you a list of the plugins that should be installed.

Secondly the contact form is not working on any of the inner pages or the contact page itself, it seems to stop working after a update to contact form 7 then the only way i could get it working again was to use my domain name provide uk2.net to host my email address this is not ideal as the from field when the form is sent always shows my own email info@balloonsbysteph.co.uk rather than the senders email address it also has been known to go to spam.

thirdly when i set up the website i didnt create a child theme and so if update my theme i am likely to lose background colours etc can you still create a child theme after creating the full website?

Security i want to hopefully prevent this hack or any further damage being caused to my site by spam etc any ideas to implement would be great?

i am happy with the look of my website and the content but fast loading etc and cashe cleaning plugin is always a great thing.