Non Diabetic with strange test results

Have had a bi of a scare re pre diabetes after a series of infections.I do use my husband 's blood testing kit to check my sugars . The other day I tested 2 hrs after a breakfast of fruit and fibre and almond milk and coffee The level was 5.5. Yesterday after an hour so of gardening , very hot and sweaty and just over 2 hrs after a lunch of 2 slices of wholemeal bread 2 poached eggs and a satsuma- horror of horrors I was 8.1
I consoled myself thinking I was perhaps a little dehydrated so I tested again this morning 10 mins after a cup of coffee and no food I was 7.1

I recall that once I tested 6.5 after fasting and then in the same afternoon 2 hrs after lunch I was 5.6 Anybody offer an explanation please?

Sorry I should have said My pre diabetes scare proved unfounded but I am due an over 60s MOT at my doctors in 2 weeks so thought I would do a bit of monitoring using my husbands test kit

Thanks Uart A further update..... a pre lunch test still with no food was down to 6.5 .Then 2hrs after a light salad lunch and a 45 min walk it was 5.1 I have been reading something about fasting glycemia which relates to higher than normal bloods after fasting. I was wondering if this is my problm since my higher bloods seem to be after fasting whereas 2hrs after eating they seem ok. Anyone heard of this ??