Nahi, swallowing cannot make you pregnant. It just goes to the stomach and gets digested. Pregnancy needs a totally different path. So relax, this is a common myth.
No. Pregnancy needs sperm to reach the egg via the reproductive tract, the mouth and stomach are not connected to that. If you ever have real doubts about how pregnancy works, a gynac can explain clearly.
No, that does not cause pregnancy at all. Pregnancy only happens when sperm meets egg through the vagina. The digestive system has nothing to do with it. Dont worry over this.