Thanks for posting your query on health care magic.
Since you had sex soon after periods which is a safe period, less likely you are pregnant.
Moreover, your pregnant test also shows negative.
Your symptoms of feeling sick, dizziness
, excessive eating and sleeping is due to effect of progesterone
in the second half of the cycle.
History of spotting is something to be of concerned.
You need to consult your Gynecologist for full physical examination and rule out trauma as a cause of spotting.
Hope this helps.