Birth control pills (BCPs) are effective in preventing pregnancy, but 5 out of 100 women can still get pregnant while taking them. Please note that BCP does not protect you from HIV nor other sexually transmitted diseases (STDs).
In order for it to be effective, BCPs must be taken daily and best not to miss any doses. It is recommended to be taken at the same time everyday for effectiveness and medication adherence.
Loestrin 24 Fe contains 24 tablets of combined ethinyl estradiol (estrogen) and norethindrone (progesterone), in addition to 4 tablets of ferrous fumarate or iron tablets. Some of the side effects may include irregular menstrual periods (especially in the early initiation periods, i.e. first 3 months), nausea and stomach discomfort, headaches, weight and appetite changes, etc. I am not sure about the metallic taste and did not find any clinical data that associate it with the 3 medication that you listed.
I understand you are scared about being pregnant. It is a good idea to use over-the-counter pregnancy test to check first and then verify with you provider with a blood test if need be.
It is very important for you to have regular follow-up visits, especially if you are taking sertraline (Zoloft) and clonazepam (Klonopin) for PMDD, or premenstrual dysphoric disorder. Some of your symptoms may also be related to PMDD.
For more information, please go to:
1. Estrogen and Progestin (oral contraceptives) - Medline Plus
2. Loestrin 24 Fe - Daily Med
3. Birth control Methods Fact Sheet - Women's Health.org