Thank you for the query.
It does not seem to be caused by aspirin
intake. More possible is that your headache and stomach ache are caused by some viral or bacterial infection. Most of such infection goes away without medical attention.
However your head injury
and loss of consciousness
should be diagnosed by your doctor. You should be examined by neurologist
and head CT might be necessary. You should also have at leas hear ECG and cardiologist consult.
Hope this will help.