Hello,
These can be the symptoms of pregnancy. There are sensitive urine and serum pregnancy tests which can detect hcg levels as low as 20 Miu for urine and 5 Miu for serum hcg test, as early as 8 to 12 days post ovulation. These are highly sensitive tests. The results can be confirmed by a pelvic ultrasonogram to visualize the intrauterine gestational sac and a positive fetal heart sound.
I hope it helps. Take care and regards.
you will have to wait to your periods due to see if it comes or its late or go see your DR and get them to do a blood test to see if your pregnant as this is most accurate and you say u had a negative result when pregnant with your son