What is wrong with me?

My husband and I are currently trying to concieve. I woke up on cycle day 17 with pink spotting, cycle day 18 brown spotting, cycle day 19 red spotting, cycle day 20 with pink spotting again that stopped that evening. I am currenlty on cycle day 21. I have also for the last 4 days been experiencing left rib pain. It hurts/aches most to the day and then is excruitatingly painful at night when I try to lay down. I have slept the last 2 nights with a heat pack on because it is the only thing that somewhat relieves the pain. Is this something that happens this early on if I were to be pregnant. Help. I really need advice. I called two different doctors about the bleeding and got mixed opinions so Im looking to see if anyone else has gone through this. Thanks in advance.