Ketones are also a sign of high glucose. they happen when the body is unable to use the available glucose due to not enough insulin and the body starts to convert body fat into usable energy becasue it mistakenly thinks it is starving. 3+ urine ketones combined with 4+ urine glucose is a cause for concern. I would be keeping a close eye on both those...on their own they are not so much of an issue but in combination they serve as a warning. I would keep a close watch on your blood sugars and keep up the fluids. The high glucose and ketones would also be a major contributor to you feeling so tired and crappy.

And yes it could all be a result of a UTI. Infection makes you even more insulin resistant and puts your sugar levels up - combine that with GD and you are a rpime candidate. So again keep an eye on the sugar levels and if you start to feel really unwell at any stage go to a hospital asap. Ketoacidosis is a very very scary and serious condition that can develop really quickly if the ketones are high for any length of time. Prolly wont happen but it helps to be aware as a heads up.
hope that helps.