Welcome Emma, you sound like you're in a similar situation to me, I have been doing 5-10 k 2 or 3 times a week for a few years, eventually entered Brighton Half last year and was pleased to finish in just under 2 hours, then got a couple of niggly knee problems and the running tailed off. Just getting back into it now, following a beginner 8 weeks to 5k plan to try and ease back in gently, but hoping to do Brighton 10k later in the year and maybe the half next year.