TTC, late period.

Hi Ladies, hoping for some advice or reassurance. My husband and I have been TTC our second child for 6 months. My period has always been to the day on time, and this month it is late by three weeks. I took a test this morning and it came back negative, and took another at the doctors also negative. I feel as though I've been having all of the early pregnancy symptoms I had with my daughter, and it's driving me crazy! I'm booked in for a blood test next week, but I guess I'm just wondering if there is a possibility I'm pregnant? Could I be further along than I thought hence why it's not showing on the urine tests? Maybe I'm just getting my hopes up too much, either way I'm desperate for some answers! Thanks!