No way, it is physically impossible to get pregnant from masturbation. Don't let these worries stress you out, anxiety can also make your periods late! Keep calm and relax.
Please don't worry, dear. Pregnancy requires fertilization of an egg by a sperm, so masturbation on its own cannot lead to pregnancy. I know how stressful these thoughts can be, but you are completely safe.
Absolutely not, don't worry. I remember having all kinds of wild questions when I was younger, but biology doesn't work that way. Pregnancy is only possible through intercourse or fertility treatments.