How unfit am I?

My husband is on a major weight loss journey, now I couldnt be more proud, I had started out on his journey with him losing weight also.
I have been in a bad place hidden away from everyone else mentally, trying to look smiley on the outside but on the inside not so much.
I started cycling a few days a week to college last September then I started making excuses to eat fattier takeaway food while in college thinking sure I cycle in and out to college I can get away with this sausage roll or wedges, or both. Biggest mistake I ever made, I have increasingly added to this with this and that but have been cycling less.
I had been thinking of getting my ass off this couch and teaching myself that I am capable of running (jogging) 5 kilometers, Hubby dearest can already do this, I couldnt keep up with him on Inchydoney beach. I need to start this training now. I cant take the dogs out Molly is still in her first heat and is at her frisky stage so Kerri couldnt come out with me as  Male dogs would probably think she was the bitch in heat, I dont want to go there.
So with at least another week to go before I can even consider taking them out for a walk, because lets face it a whole lot of people play ignorant to their responsibilities as dog owners and just let them wander where ever and when ever they want to, fully intact, especially the males, now I know my pup is not yet neutered but due to financial circumstances I was waiting on a voucher to get her neutered and she went into heat a day before the vouchers were issued and due to demand they could not hold onto a voucher for me. So she can not be neutered until at least April.
I need to do this "training" I think while in college, between classes or something, I have just over a month to move these cankles that feel like lead when I attempt anything more than a spirited walk.
I really dont want to let myself down but would love love love to Join this race that hubby dearest has been ask to lead out in April as he is seen from his followers as an inspiration in his life changing journey, I still want to be part of it but need to get my head out of the doldrums to get myself back into gear.
I really need one of those preverbial kick's up the rear.
Inspiration please hit me with a whallop!