Brief Answer:
Diabetes Unlikely

Detailed Answer:
It is unlikely you have diabetes based on the information you have provided but one cannot be 100% certain unless tests are performed in the standard way.

There are 3 such ways to go about ascertaining whether or not you have diabetes versus pre diabetes versus normal glucose tolerance/metabolism.

They are

1 Fasting glucose test

2 Oral Glucose Tolerance test using 75 grams glucose challenge and checking the 2 hour reading

3 Glycosylated Hemoglobin also called HbA1c

Normal blood glucose levels are

65 to 99 mg/dl in the fasting state.

100 to 125 is considered Pre diabetic i.e. a risk factor for the development of type 2 diabetes. An alternative technical term for this condition is IFG (Impaired Fasting Glucose).

126 and above is tantamount to a a diagnosis of diabetes

Post prandial the blood glucose levels normally remain under 140. However the standardised way to assess this is through the 75 grams OGTT (Oral Glucose Tolerance Test).
2 hours after the glucose load, blood glucose levels are

Normal if less than 140

140 to 199 is Pre diabetes or IGT (Impaired Glucose Tolerance)

200 or more is sufficient to make a diagnosis of diabetes.

Random glucose levels of more than 200 with symptoms of high blood sugar such as increased thirst, urination, hunger and weight loss are also sufficient to make a diagnosis of diabetes.

So you seem to have IGT based on the 2 hour value of 145, although this is best determined after a proper 75 gram glucose challenge and not just any meal. It is quite likely you have Pre diabetes. But to be certain whether or not you have diabetes, one needs to do either the OGTT or Glycosylated Hemoglobin (HbA1c) test.
This is because some people have post-meal glucoses in the pre diabetic range but their fasting readings or the HbA1c cutoffs could meet criteria for diabetes.

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Brief Answer:
Follow up

Detailed Answer:
Diabetes can cause weight loss.

However, your weight loss is unlikely to be due to diabetes because it is unlikely you have diabetes in the first place.

Weight loss in diabetes typically occurs when the glucoses are running persistently high in the 200 plus range. Your glucose levels are not quite there.

So it is most likely that your weight loss is due to your lifestyle changes i.e. the healthier eating and increased physical activity.

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Brief Answer:
Second follow up

Detailed Answer:
It is possible you might a condition called reactive hypoglycaemia. However this does not occur immediately after eating. It tends to happen few hours after the meal when the sugar levels drop sharply.

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Brief Answer:
Third follow up

Detailed Answer:
Specifically there is a condition called diabetic retinopathy which takes several years to develop.

There are many other eye problems that can occur in people with diabetes such as cataract and glaucoma to name a couple.

There is no fixed duration of time for any complication of diabetes.

It varies from person to person depending on the degree of diabetes control also.

But in general, eye complications take several years.

However, blurred vision can also occur if sugars are running high such as above 200 to 250 due to 'osmotic' changes in the lens of the eye. This normalises once the sugars are brought under control

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