Unlikely . Although no sterilization is 100%, pregnancy is unlikely. The failure rate can be from 1:1,000 to 3,500 depending on the type of procedure performed. If you have symptoms though, check a urine preg test ASAP. You have a very high risk of ectopic if your procedure fails. If you want a normal pregnancy, tubal reversals are possible vs in-vitro if needed. Talk to your Doc and trust your TL. .
Not likely. It is highly unlikely to get pregnant. You were taught this when you consented to the surgery. Nothing has changed since then.
Possible, not likely. Even when the tubes are tied, clipped and burned, they can grow back and become open. Pregnancy would be very unusual, but not impossible.