First of all, do a blood test
for beta hcg & USG lower abdomen to confirm or exclude intrauterine pregnancy
as early home pregnancy test may give false negative result. It seems to more likely implantation
If you get negative result again, then other reasons of spotting like hormonal
imbalance, stress/ anxiety, thyroid problem, wt gain/extreme loss, irregular eating habits etc. are needed to be ruled out properly.
Do some investigations to rule out underlying pathology like Thyroid profile, LH/ FSH, Blood estrogen & progesterone
level etc. So consult with your doctor and take suggestive measures.
Avoid stress, take healthy diet, control body wt and need proper sleep. Tender breast is due to progesterone hormone. Use tight breast support for discomfort and take prime rose cap.