haven't had a period since Oct ...

Hi,
Welcome to ehealthforum.
Sometimes it can take few months upto 1 year’s time for fertility to return after you stop with your hormonal birth control use (depending on type and duration of the birth control used). It is also possible that you are pregnant and the tests are showing false negative results. The symptoms of absent periods, mood swings, vomiting, nausea, increased sleep, could also suggest pregnancy chances. If pregnancy is suspected, consider visiting your doctor/gynecologist for thorough examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately).
If pregnancy gets ruled out, and if you have been trying for pregnancy but have not been successful, you should consider getting a complete infertility work-up done for you and your partner to see if there are any underlying causes for the infertility/inability to conceive. There are many factors (ovarian, uterine, hormonal, stress etc) that govern the chances of having a successful pregnancy. Hormonal issues, problems involving ovaries and ovulation, uterine problems, tubal blocks, cervical or vaginal infections, post-contraceptive ovarian failure/suppression etc., should be ruled out for you. For your partner, semen analysis should be done to rule out infections and to confirm the quality and quantity of sperms produced. Treatment as needed (based on examination and investigations results) would be started to help you get pregnant. Consider visiting your gynecologist/obstetrician for further evaluation and assistance and be in regular follow-up and monitoring as instructed. Have diet with foods rich in zinc content to ensure better maturation of egg and sperms. Monitor cervical mucus changes and the BBT (basal body temperature) charting to predict your ovulation and time your intercourse for having fruitful results. Have intercourse in positions that allow for deeper penetration for high deposit of semen.
Take care.