I've just been reading some of the old comments re the Merina IUD.
I'm alarmed at how many women experience pain and ask if this is normal. It's NOT normal to feel pain. It's your body telling you there's something wrong.
A young woman I know had such pains, and went to her doctor. The IUD was beginning to come out, so the doctor kindly pushed the Merina back up. The pains continued. Eventually she asked him to take it out. He couldn't get it out. She went to hospital. The hospital told her the Merina had embedded itself in the wall of her uterus and it was highly unlikely that she would be able to have anymore children. Surgery was done to remove the device. The pain has stopped. They told her after the op she has a 50:50 chance of conceiving. She's not too worried as she has two children. She said it would be a disaster if she'd been single and childless.
There are other ways. I know many women don't like to engage with their contraception, but it's your body, you need to listen to it. If you want a safe method that you can work with and become more aware of your cycle, try the diaphragm or the mucus method.