Hi OP I think it is really normal to have a slump round about 7 months after a breakup. Adrenaline has kept you going until now and it is just starting to sink in that this has really happened.
It's a good thing that you are going for counselling shortly. I went at about the same stage and found it very helpful.
I think it is also normal to start discovering the joys of being alone. I certainly did. My exH loved parties and would stay until the bitter end. I hate them so one of the first decisions I made was that I was never going to another party and I haven't :) I just plead a prior engagement.
Most people do move on to another relationship at some point, but it sounds as if you are not ready yet. Now really is the time to put yourself first and look after yourself.
If you don't want to go to the gym, ( I wouldn't either), how about a walk in a local park or take yourself off to a country pub for a stroll in the countryside and a nice lunch or join a local netball team or sign up for a climbing wall or learn to canoe or sail or surf - whatever you fancy, you are free to choose now so choose something fun.
If you CBA to shower, how would you feel about swapping it for a soak in a hot bath with lovely scented oils and a candle burning instead?
See, you don't have to suffer, you can do things which are good for you, but which are treats and IME the way to build yourself back up again is to look after yourself and do what feels good.
I think a large part of being a happy single is amassing lots of things which you enjoy doing and doing them regularly. For example, although I work on computers all day, I always buy the actual newspaper rather than reading it online and look forward to sitting down to read it with a cup of coffee before I start work. In Summer I sit out in the garden to do it. That wouldn't be a treat for lots of people but actually it is something I really enjoy and choose to do daily.
Or another example: I love the smell of a particular brand of hair conditioner so I always make sure I have a supply of it and I use it at weekends only (so it remains a treat). Aim for at least 4 or 5 small treats or pleasures a day which work for you and have fun finding them.
Your breakup is still pretty recent and there will be good patches and bad patches, but the overall trend will be upwards.
And yes I think it is also normal to still have some kind feelings for your ex, but also recognise that they are really not worthy of your time and attention and you will not get back together. It just means that you are a decent empathetic person. Thankfully it is no longer your job to fix him!