Conception does not happen during sex. Conception can take a few days after sex. It takes those microscopic sperm a long time to get to the egg!

You may have bled from your partner banging up against your cervix. Which could have also been your pains.

Might I suggest a barrier method of birth control? Like condoms or a sponge or something that is not hormonal and you won't need to remember until the heat of the moment.

a feeling inside lik when you ovulate? are you trying to say you can feel ovulation?!

Yeah, it's just like a little pop/twinge inside.

It's more likely that you experienced breakthru bleeding from starting/stopping your pills. Your hormones are probably out of balance, which can cause bleeding/spotting.

You definitely didn't experience implantation bleeding the same day you had sex. Sperm aren't that fast.

I can feel when I ovulate too - it's not common but not that strange either

Agree with the others, you won't have conceived that quickly but you're not taking your pill properly so you're not protected from the risk of pregnancy. Either take your pill EVERY DAY (it is especially important with the mini-pill to take it same time every day) or perhaps get the Depo Provera jab so you don't have to think about it. If you think hormonal contraception isn't for you then a barrier method is a must.

It is called Mittelschmerz

Ovulation pain; Midcycle pain
Definition

Mittelschmerz is one-sided lower-abdominal pain that occurs in women at or around the time of ovulation.

Causes, incidence, and risk factors

About 20% of women experience mittelschmerz, or pain associated with ovulation. The pain may occur just before, during, or after ovulation.

There are several explanations for the cause of this pain. Just prior to ovulation, follicle growth may stretch the surface of the ovary, causing pain. At the time of ovulation, fluid or blood is released from the ruptured egg follicle and may cause irritation of the abdominal lining. Mittelschmerz may be felt on one side one month, then switch to the opposite side the next month, or it may be felt on the same side for several months in succession.

The pain is not harmful and does not signify the presence of disease. In fact, women who feel this pain may be at an advantage when planning or trying to avoid pregnancy. A woman is most likely to become pregnant just before ovulation, on the day of ovulation, or immediately after ovulation. However, birth control methods that rely solely on predicting ovulation are far from completely reliable.

Symptoms
Lower-abdominal pain that is:

One-sided
Recurrent or with similar pain in past
Typically lasting minutes to a few hours, but may extend as long as 24-48 hours
Usually sharp, cramping, distinctive pain
Severe (rare)
May switch sides from month to month or from one episode to another
Begins midway through the menstrual cycle