Can periods be altered due to the morning-after pill?

Hello doctor,

I am on birth control pills, and I had sex last week. He did not cum inside me, though. However, there might still be precum. Plus, I usually always take my pills at 8 p.m. I know I have a 2-hour window. But after three days, I took it at 11:25 p.m. and the next day at 9:55 a.m. Shortly after sex, I could not find my pills. I panicked because I was on vacation. I went to the pharmacy and bought similar pills. I also took a morning-after contraception pill called postday one. However, I started reading online after that there are usually two pills to take, but the morning postday pill only had one, and in the directions, there was no mention of taking another one. I called the pharmacist, and she said that some pills come with the full dosage in just one pill. I want to know if this is true. I also want to know, if I was protected since I took my pill two days later after that at 8 p.m. and had sex the next day morning, and I also took the morning-after pill called postday one. How soon can I take a pregnancy test, just to be sure? Plus, what happens if I take the test, it comes out negative, and then I do not get my period? Could it be messed up by the morning-after pill? What about if I do get my period? I also heard you can still get your period while you are pregnant. Can I trust if I take the pregnancy test and it comes out negative, that I am safe?