You had your intercourse nearly during ovulation period. You are trying to get pregnant, what you experience may not be signs of pregnancy
Signs of pregnancy or implantaion does not happen so soon after intercourse.
, blood, stomach ache may be due to a rough sex between you
This may cause abdominal muscle contraction
which may make you feel nauseous.
You could take anti-spasmodics if this pains are worse. and also analgesic
for back pain.
This is nothing to worry about. You could have regular sexual intercourse if both of you are comfortable.