Gf and I are really concerned on whether she may be pregnant despite constant use of protection.

We're both adults, but pretty young. To preface this, we first had sex 2 weeks ago. And that time, as well as every time since, I've worn a condom, and made for sure that it wasn't leaking. So, ordinarily, I'd feel confident it's fine. However, today, as well as the last two days, she has had spotty bleeding in the morning after waking up. We looked it up and found it could be "implantation pregnancy", based on it fitting the symptoms, so yesterday she bought 5 tests from the dollar store and 2 tests from Walmart of a higher quality. The first one she took kinda said pregnant, but we think it was messed up because it made more of an "H" than the typical two lines. Each of the 5 tests after that all said negative, one of them she took this morning. However she bled again today so she's still worried, and I can't help but feel worried too. One of her coworkers who has had 4 kids insists she probably is pregnant, due to her having headaches as well, whereas others say she doesn't have to worry about it. The thing about the headaches is that she grinds her teeth in her sleep really bad, so loud I can hear them over videos I'm watching, and I know this leads to headaches upon waking cause I used to have the same problem. Furthermore, she hasn't gotten any cramps. She has been bloated, but this could also be because she's eating a lot more than she used to because she's trying to gain weight

We're just super nervous and I would appreciate any sort of clarity this subreddit may provide. We're both young adults, and incredibly nervous about what we would do.