Implantation bleeding?

My husband have been trying for 2 years for baby#2 & for the past 2 weeks I have been real nauseous after eating certain things. Today after being up for about 2 hours I had a felling of having a discharge and I went to check and it is a light brown color. I never have a discharge so I'm wondering if these are all signs of possible pregnancy?? I also started with sore breasts last night. I didn't have a single symptom with baby #1....