It takes about 7-10 days after ovulation for implantation to occur (if conception happened). So there is no way you could tell if you are pregnant before that time. It takes another few days for the hormone to start being produced and to build up enough for a pregnancy test to detect it. So the earliest you can test is around 2 weeks after ovulation. This is why pregnancy tests are supposed to be used no sooner than around the time your period is due. If you don't know when it's due (since you don't have a schedule as you said), then I would just test 2-3 weeks after you had sex. Also, it is hard to know when you are ovulating, especially with irregular cycles.
I don't want to be judgemental, and please don't feel like you have to justify anything to me, because it's none of my business, but it sounds to me like you are making excuses to yourself about the reason you
are not using protection. Maybe you're not being honest with yourself. If you want to get pregnant, then that is fine, there's no need to defend why you aren't using birth control. Just admit to yourself that you want to be pregnant, and stop making excuses.
If you don't want to be pregnant, and condoms and pills aren't an option for you, which is fine too, then you should look at other options. Diaphragms, sponges, spermicides, etc can all be used. If you are serious about not wanting to be pregnant, then you should find a reliable method. You need to decide for yourself what is more important to you; preventing pregnancy even if it means you have to use something you "don't like", or accepting the risks. Only you can decide. Just be honest with yourself.
As for how easy it is to get pregnant, it depends on lots of things. On average, you have a 20% chance of getting pregnant each cycle, and lots of things have to happen for tha to occur. It depends on timing, you and your partner's health/fertility, etc.
Good luck, whatever happens!
