Am I Pregnant?

Hello! I’m currently having a pregnancy scare, which is not good because my partner and I have recently split. Here’s some information:

1. My usual cycle length is 34 days but I have very irregular periods.

2. Supposedly I had sex during my fertile window. I’m not 100% sure because I didn’t test but I had the symptoms so I’m assuming the app predicted it correctly.

3. I’m on cycle day 31, so the late luteal phase I believe.

4. I have taken some pregnancy tests but they’ve come out negative. Another <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a> app I have says that I can take a pregnancy test in 3 days though.

5. I haven’t taken any emergency contraception. We didn’t use any protection at all, actually. They didn’t pull out either.

Some extra information: I’m currently experiencing light brown spotting. It’s very minimal and I only see it when I wipe. I’ve been experiencing cramps (that are sometimes throbbing pains, not too intense though) and lower back pain. I do feel nauseous and dry heave a lot but those symptoms I don’t count because I have another condition that causes me to feel frequently sick. Could I be pregnant?