Need help

Okay I need help. My last period was june 9-13. I've done pregnancy tests and all come back negative. I've been to a doctor and have told her everything I have been feeling and what's been happening to my body. She said by what I've told her and what's she has seen that I am just to early to show on a test. I have a order to get a ultrasound done but I can't get it done right now due to money. Is there anything I should be doing to figure out if I am or anything that would help me. Thank you