Most chemists will do free or cheap sugar bllod tests at the dispensing counter- quick prick of a finger, and immediate results. Anyone over 55 is well advised to have it done once a year- try to get to the chemist's early in the morning BEFORE you have breakfast, as it gives a better assessment of your true sugar levels. If it is high, they will advise you to go and have the HbA1 test, again first thing in the morning, fasting- that will give your average sugar for the past 3 months- and refer you if necessary.
It's quick, cheap or free- just do it - the sooner diabetes is diagnosed, the sooner you can make life changes that can make a huge difference, and also get medication and if necessary, insulin- that will stop further damage to your eyes and so much more- before it is irreversible.