Thanks for all the helpful comments everybody, they have really helped boost my confidence.
I haven't jogged since last Wedensday due to a back problem (which funnily enough has actually turned out to be a stomach problem) but after being given a prescription by my GP I'm feeling much better and really looking forward to running home tonight.
I feel so guilty for having missed a week! Haha.
Rita, I have taken on board your advice re a running log and I am now recording all my daily exercise, incluing walking, swimming, etc. You're right, it does help!