Advice please...

Hi ladies. I could use some advice as I am very scared. I know the only true way to know if I am pregnant is to wait and take a test but this would be my first time and I am not ready.

I am on birth control and I take it religiously everyday. My partner and I had intercourse about 3 days after I started my new pack. I was put on UTI medication 6 days after intercourse due to frequent urination. I’ve been to the gyno several times over the past two weeks. I’ve taken 4 pregnancy tests (all negative). She doesn’t expect pregnancy but isn’t ruling it out 100%.

My period is due tomorrow. I started spotting yesterday (which typically I never spot before a period). It was dark brown. Over the past 24 hours on a tampon there has been dark drown blood mixed with red blood mimicking the start of my period. Could this be implantation or my period starting early?

I have never been so stressed.

Thanks for reading and any advice given.