Indeed, as u got the depot shot 7 days AFTER, it sure cannot protect u from pregnancy
. Indeed, some of the symptoms described can be as a side effect to the depot harmone injection, you NEED to rule out pregnancy as soon as u can. A simple internal examination would be better, followed by a usg if required.
If you have a history of headaches
then the harmone inj may not be the best choice for you for contraception
with best wishes