It's worth paying £2 for a full credit report, which will tell you what everything is for. Companies sell debt on to collection agencies, and it all gets very confusing. You could have more than one company chasing you for one debt. Remember that if any of these debts are more than 6 years old, and providing that you have not paid anything towards them or admitted that you owe the money, they are no longer enforceable.
Work out which are your priority debts: council tax and electricity would seem to be the 2 most important of the ones you've mentioned, anything that is consumer credit is NOT a priority. Concentrate on those, especially as clearing them will leave you with more disposable income.
In the longer term, there are only 2 things you can do: spend less or increase your income.
Cut back on everything you can, and when contracts are up for renewal, do price comparisons and go for the cheapest you can find. Could you take a mortgage holiday for a month or two, and use the money saved to pay off the electric debt or the council tax? And check that you're not on a variable rate for your mortgage. Can you get a more economical car? Collect vouchers, use your loyalty card points, eat like a pauper (you could even try Jack Monroe's eat for threepence a day recipes). Unless you're under 25 or have only recently passed your test, your car insurance seems high. Get a cheaper deal when it's due for renewal.
To cut back, you really need to know where it goes, so work out exactly what your money is spent on, down to the last Mars bar. Then cut out anything that isn't essential, or find cheaper alternatives. Pet food: if any of your pets are dogs, put them on a working dog food which will be vat free and won't do them any harm at all. Shop at Aldi/Lidl, cancel any gym membership, subscriptions etc. Go back through at least a year's bank statements in case there are any you've forgotten.
Sell anything half decent that you don't wear or use (my mate made £220 in a morning selling at a boot sale last summer). Consider getting a lodger if you have a spare room, a second job or doing overtime if it's available. If you've had spells when you weren't working, might you be due a tax refund?
Money Saving Expert is a brilliant source of tips and advice, and definitely contact one of the debt charities when you know exactly what your debts are.
Overall, your financial position isn't too bad. £500 a month after paying your bills should be more than enough to keep you fed, clothed and treat yourself occasionally. DP and I live on about that much, and we run 3 vehicles between us.
Oh, and look into the possibility of you having paid PPI for something over the years. Even a small PPI refund would make a difference.
You will be able to get through this, and once you've done it, you'll probably develop a much better attitude to money/credit.