You should have life cover with specified illness cover at least to cover your debts and maybe a couple of year's salary too given that your son is only 18 and probably going to college.
Are your life cover premiums reviewable?.. I assume they aren't guaranteed and will go up over time. A term policy e.g. for 10 years can work out a lot cheaper and will not provide cover for longer than you need it. Joint life is also cheaper than dual. If it is to cover a loan, why not get decreasing term cover?
Your existing policy may have a value if you cancel it which would provide a good start to putting some money away for any eventualities.
If you are semi-state you probably already have sick pay, PHI and death in service benefit so try not to have too much life cover as it would just be an unnecessary expense.