Is my girlfriend pregnant?

I (24m) and my girlfriend (20f) are kinda scared right now and need some guidance. My girlfriend is extremely regular with her periods she says. We had a lot of sex while she was ovulating in early to Mid January, her period was due the 23rd. We found out later that the condoms we used during this time may have been old, not expired but like 1-2 years old. Complicated story, won’t get into it, but we didn’t know at the time.

She missed her period that was due on the 23rd. We tested 4 days into her missed period with one test from one of those ClearBlue Triple Assurance tests, and it came back negative. Just to be safe, we tested again 10 days after her missed period, with the other two tests, and they both came back negative. We breathed a sigh of relief.

But now she is spotting she says. Dark brown spotting. She still hasn’t gotten her period. And it has sent me down a spiral of worry again. The tests said they would be accurate at that stage into a missed period. 10 days into a missed period it should be extremely accurate from what I’ve read. Can someone please help us?

Tldr one negative test 4 days into missed period, 2 negative tests 10 days into missed period, but starting over the last few days she’s been spotting.