Can I get pregnant 2 days after my period ends even if I took the morning after pill the next day?

If you are relying on an app/website to tell you when you're fertile, then it is just an estimate.
Most women are fertile around the middle of their cycle, assuming their cycle is an average monthly one, & always regular.
However, in the days (up to 6/7 for some women) prior to ovulation, the cervical mucus changes, in order to preserve any sperm it comes into contact with, ready for when you ovulate. This means that you can become pregnant from sex you had up to 6/7 days (at most) before your ovulation (usually more like 3-4 days before).
As a guide, many women actually ovulate around day 14/15 of an average monthly cycle, but are fertile (mucus changes) from around days 10/11. To be safe, I always go with a fertile period of around days 10-18. I use ovulation kits & also monitor my family planning/fertility signs each day.
A guy does not need to ejaculate to get you pregnant, & sperm can be present in his pre-ejaculatory fluid (pre-cum), whether or not he has urinated since his last ejaculation (see the recent study online by Human Fertility).
Plan B works by delaying ovulation until the sperm is out of your body. If you are already ovulating when you have unprotected sex, then Plan B cannot work. You'd either need the other pill, Ulipristal Acetate, or to have an IUD fitted by a doctor. Either of those things can be done within 5 days (120hours) of the unprotected sex, whereas Plan B may only be effective up to 3 days (72hours) after unprotected sex.
It sounds as though you caught things just in time, but it's not impossible that you could be pregnant.