Starting birth control pill on last sunshine of your cycle + other medications sound out?

Hi everyone, I have 3 question,

1. I've started on birth control pills again, however i started on the last time of my menstrual cycle (last day of bleeding). I know you're supposed to start from the first afternoon of bleeding. the doctor told me it would decrease the usefulness of the pill for the rest of the month. however, on the instructions inside the packet it said if pill was started from 5-7th time of cycle, it would decrease value of the pill for the 1st week, but i would be protected for the rest of the month. Which one should i believe? anyone had personal experience?

2. Is at hand a possible chance of pregnancy if unprotected sex occur 1-2days before your menstrual cycle? (this is a moment ago something i've been pondering on for awhile)

3. I know antibiotics affects BC pills, but does diet pills affect the usefulness of bc pills at all? i.e. diet pills that speeds up metabolism by X-times, since those tablets increase heart rate and blood circulation.

THANKS :)
Answers:

If a woman have HPV can they pass it on to males? but this woman have never had an outbreak ever?

1. i have a sneaking suspicion that you should rely on the instructions inside the packet, but to be sure, use back up protection for at smallest 2 weeks. as my experience and my understanding, depending on the pill brand are instructions when to start off, what to do if you missed pills or started late, i believe what the factory owner said because they won't print that if it wasn't tested, right? and as for the doctor, he/she may generalize the effectiveness of the pill, not by brand.

2. i surmise it's safe even if semen can live inside a woman's body for 3 days or so. since you have your menstruation, i doubt you are pregnant.

3. about the diet pills, i've search for it here in the network, because i've been wondering also just about that and some diet pills/tea have some caring of herbal ingredient and sometimes also something that acts as laxative. similar to i think diarhea affects the effectivity of the pill, so still i don't know. adjectives i've read is that some herbals do affect the pill, but none of them was stated but the st. john's wort. (i'm using the slimming tea right presently, but i take precaution that it might affect the pill so, i asked my husband for us to use condoms or subtraction method in codicil to my using of the pill.

i hope this helps...