Yes - take a test
A missed period and/or positive pregnancy test are signs of pregnancy. Take a pregnancy test.
Yes, if you stop using the patch as directed, you could get pregnant.
Maintain your patch change day irrespective of when your period begins and ends during your 'patch free' week. For example, if your patch change day is a Saturday and during the 'patch free' week happen to continue bleeding on the Saturday of that week, still restart the patch on that day.
The signs of pregnancy are a missed period and/or positive pregnancy test. Take a pregnancy test to see if you're pregnant.
Your period may be delayed after stopping the patch. If you had unprotected sex after stopping the patch, take a pregnancy test. If you don't' want to get pregnant, find a new effective methods of birth control.
You may have breakthrough bleeding if you don't use hormonal birth control as directed. You are unlikely to get pregnant from changing your patch one day late, but it's possible.
The patch and all oral contraceptives are based on the theory that you will ovulate after 8 days without the hormones. If you are removing the patch for the seven days during week four and don't put on a new patch at the beginning of the new week you could ovulate on the 8th day.
If you did not use the patch as directed, you could be pregnant. Take a pregnancy test no sooner than ten days after sex. Start the patch again or change to another effective method if you don't want to get pregnant.
You can't get pregnant from switching brands of birth control patch as long as you have a patch on during the appropriate days, and aren't late in putting on the new patch. If you go more than seven days without a patch, you may be at risk for pregnancy.
The patch has to be changed each week. You can change the patch weekly for six weeks, without a week off, if you like. If you do that, there's no additional risk of pregnancy. If you leave the same patch on for six weeks, you could get pregnant.
Yes it can. Discontinuing the patch will likely change your regular cycle, usually by delaying the onset of menses right after going off it. What appears to be a "missed" period is likely a long-delayed one. Yes it definitely can. You can have irregular periods for 3 months AFTER stopping the patch.
If you use it correctly for at least one week, the birth control patch is effective even if you're bleeding. You still have protection during the patch-free week if you used the patch correctly in the previous weeks.