Talk to Nephrologist on Oliguria

I have been facing a low urine output issue for 1 year, which is still persisting. Before this problem started, for 3 to 4 months, I used to urinate a lot—it felt like the output was double the amount of water I drank. But for the last 1 year, it has been very low.

Symptoms: Even after drinking 1 liter of water, only 100ml of urine is passed, which is amber-colored and concentrated. I have puffy eyes, and pressing my legs or feet leaves a mild dent. Drinking even a small amount of water makes my upper abdomen feel full for an hour.

All lab tests are normal, including RFT, LFT, BP, USG of KUB, CBC, UACR 5.8mg/g, and UPCR 0.08mg/mg. Please tell me what could be the problem? Why is the urine output so low and why do I have all these symptoms?