Thanks for posting,
can not be determined on the basis of the symptoms you presented. The headaches
might be due to the presence of a systemic infection or gut infection. Constipation is still premature to be related to pregnancy and headaches are hardly a symptom of pregnancy except there is an associated diseases such as hypertension
How ever, your problem has to be looked up as a couple fertility
problem which could be corrected if you guys can meet up with a fertility specialist or gynobs. The first thing you should do is get a pregnancy test if you feel that you have missed your period for more than 5 days. The next thing is consult a doctor with aptitudes in managing fertility issues. The problem of not conceiving might not be coming from you but from your boyfriend reason why both of you need to consult, get checked up. You both have to be tested for STDs, his sperm analysis done, your tubes and pelvic region checked.
After which the health care practitioner will give you the next step to follow in conceiving a little one.
Hope this helps and wish you the best