There's more than one reason for having glucose in your urine. Yes, it can be in your urine sometimes, and not in others if you have diabetes. I don't know if you're seeing a doctor and having the urine tests or doing them at home, but glucose in urine without high glucose levels would not be diabetes but something else. It is possible that you ate a large amount of carbs before the test, but doubtful. A normal functioning body would not allow glucose levels to rise to the point that the kidneys would need to flush excess glucose levels. Finding glucose in the urine requires further testing. You should be tested for high glucose levels and/or ketone levels WHEN your urine glucose level is elevated. That will rule out out diabetes. I don't know whether you're male or female, but it's common for pregnant women to have glucose in their urine without diabetes (high blood glucose levels). Hang in there, you'll get it sorted out when you have those tests done. Don't worry...you'll be fine.
All I can tell you is my experience.
When I was about 17 or 18, I was 5'8" but only weighed 118 pounds. For a guy, that was pretty thin, and my doctor told me to gain weight. By the time I was 21, I had not gained any weight, but did notice from time to time, I would break out in a cold sweat, and get all "shakey feeling" like my whole body was vibrating. I was also exceptionally hungry. Other times I had a bad headache, blurry vision, and was generally groggy and almost like I had been drinking.
If I made the mistake of eating something high in sugar, I felt great for an hour or two, but then I would deteriorate through the above feelings, to the point where I was dizzy, confused, and extremely pale-looking. I never did pass out, but came mighty close. I called this "crashing".
Friends of mine eventually convinced me this was not right, and I saw a doctor. To my surprise, I found that I would "switch off" periods of time where I had low blood sugar (crashes), and high blood sugar (headache and blurry vision). When I was young, these switches could happen as frequently as every six months or so.
My tests showed that just prior to a crash, I had an exceptional amount of sugar in my urine. This would continue until my blood sugar level reached about 35, which is very bad. One of the glucose tolerance tests I took had to be stopped, and I was given a shot of something to bring my level back up to a reasonable level. I was kept in the hospital over night, too.
At that time, I went on a sugar-free diet and attempted to control the highs and lows this way, without medicine. Pills and shots were not a good idea since my symptoms would swing back and forth so rapidly.
With the diet and careful monitoring, I went along fine until just a few years ago. I am now 50 years old, and am now "officially" a diabetic. My first symptom of that was an unusually fast weight gain. I gained more than 100 pounds in a little over a year. I am now on several medications, and am working on losing these extra pounds. I have lost almost 60 of the little buggers so far.
As my weight goes down, I am finding that my sugar levels are easier to control, and I "spill" sugar in my urine less.
If you have diabetes in your biological family, you may be developing some early symptoms like I did. It is probably best to see a doctor, and to see about monitoring your blood sugar levels. If you can keep your blood sugar relatively even, you will find less urine sugar, and reduce your chances of kidney damage as you age.