I am new to this site so please be gentle with me!!!! I found out I was pregnant on Monday and since the weekend have been having stitch like pains on and off on my right hand side. I think I had this with baby no 1 but cannot remember. I presume it is everything settling down but just wanted some reassurance and to help my pregnancy paranoia!
Sounds like implantation to me too. It's very common in early pg to feel as though AF (period) is about to show up. Unlike most other mammals humans do not have a dedicated area of the uterus for a pregnancy to establish hence the discomfort felt by many women during implantation. That and ligament stretching would account for the stitch like pains. Without wishing to worry you, you do, however, need to report any severe pains and/or sharp increase in temperature as this could indicate an ectopic.
I am 4 weeks pg too (almost too scared to type it) and I have been having lots of sharp pains like something unnatural is burrowing into my abdomen... I remember feeling this with my first pregnancy, so I guess for some people it is normal. Good luck with your pregnancy!!!!