5.5 is top end of normal for fasting, and statistically people with fasting blood sugar of 5.0 upwards are more likely to develop type 2 in the next few years.
However, you can not diagnose diabetes on the strength of one finger prick test. The meters have a 20% accuracy tolerance, so it could actually have been 20% lower (or higher). Some meters are far less accurate than others. You may not have washed your finger properly. Etc.
The best way to be sure is to see your doctor and to ask for an h1bac test (that’s an average blood sugar over the last 3 months or so) and a glucose tolerance test. But if you don’t have time for that, or want a clearer indication at home first, you can do your own test (this is just to give you an illustration; you should still go to the doctor for a proper check):
- fast overnight for 10 hours or more
- take and record your fasting level
- consume 75g glucose (drink lucozade or similar, but you’ll need to check label as they’ve changed lucozade now because of the sugar tax)
- sit very still for 1 hour
- test and record reading at 1 hour
- sit very still for another hour
- test and record reading at 2 hours
Ideally you want to be under about 10.0 at the 1 hour and under 7.8 at the 2 hour readings.
However - diabetes isn’t so much black and white as it is a slippery slope, and the cut-offs are rather arbitrary. If you’re close to the borderline, your blood sugar response isn’t entirely “normal” and may well warrant further testing and pre-emptive measures like cutting carbs down, especially refined carbs, and doing more muscle building exercise. Plus a diabetic friendly diet is generally a healthy diet - lots of meat, fish, eggs, some cheese and nuts, and lots of veg, esp green leafy veg - you can find loads of decent recipes online.
I think it’s very wise to check it, as so many people have undiagnosed higher blood sugars, but the best way to do that is a proper regular medical check-up. Good luck!