Possibility of pregnancy?

My period is 5 days late which I’m never this late. My cycle is 28-30 days and I had sex on days 18 and 25. The past couple days I’ve had on and off spotting, it’s been very light and either brownish or light pink color. today I also started getting cramping in the middle of my abdomen which I never cramp during my period and I also have some lower back pain. The sides of my breasts are a bit tender but nothing too terrible. I’ve also been peeing like 3 times an hour which is a lot for me. I’m 21 and this is my first time ever thinking I might be pregnant so I don’t know a whole lot about what symptoms to look for.