I was told I had a thick uterus linning caused by hormonal imbalance, its 3.5cm x 7.93 cm. I have early signs of pregnancy but - test. What is normal?

Something not right. Those sound like measurements of the uterus and not the uterine lining. Verify those numbers with your doctor. If those numbers are correct for the lining then this needs prompt evaluation and a biopsy. I suspect these are not the lining measurements but rather the measurements of the uterus. Pregnancy tests are reliable. If you doubt the result simply repeat in a few days.