what garment to buy for that won't cost much in white color

Hi use may think it's silly but what does implantation feel like ? With my other 2 I had a implantation bleed always thought I was about to come out but we're trying for no3 and I'm due on next Saturday an my body feels totally different I've had 2 sections and just above my scars bottom of belly it's been aching like someone's pulling on my stomach then a few sharp pains is this cos I'm gunner come on or could it be implantation ? I've never had period pains so I don't know what there like lol sorry for long post an if I sound dumb Tia x what garment to buy for that won't cost much in white color