I too had a deeper kind of groin pain. I researched vaginal pain to see if that was normal and apparently it's very normal early on due to stretching of ligaments caused by the pregnancy. I never had spotting.
i had almost that exact pain early on, around 4 weeks. gentle stretching pretty much resolved it for me. (e.g. lunging with your left leg back and left knee on the ground, so that the inguinal area gets a stretch). i believe it's normal, and the fact that you didn't spot in conjunction with the pain is very good. there's no harm in getting checked, though, if it would put your mind at ease.
Cramping and bloating are normal in early pregnancy. The general rule is cramping is fine and spotting is okay, but cramping and spotting at the same time can be bad. It sounds like you just had spotting the day of your expected period and that also is normal.
If it gets worse or if you have any other signs like a fever or pain when urinating then I would call the dr and insist on being seeing right away as that could be an infection. Other than that you should trust your gut instinct if you feel like something is wrong call the dr that's what we pay them for.
Good luck and congrats.