1. Yes, it counts as a late pill.
2. No, it does not increase your risk of pregnancy since you only missed one.
3. No, birth control pills reach maximum effectiveness after just one week.
4. I have no idea about taking 4 pills. I believe only very specific brands of pills can be used this way. Besides, you don't need to.
5. I do not believe antidepressants or your libido affects your fertility at all in this case. Your fertility is only affected by the birth control.
6. I don't know how much something like Plan-B costs but if I had to make a random guess I'd say $20 for a box. You don't need any right now anyway.
7. Again, I do not know if yasmin can be used as an emergency contraceptive; but you don't need to do that since you are not at a higher risk of pregnancy.