What’s wrong with me!!

Uhggg I’m mainly posting to vent since I literally can’t talk to any of my family and friends since no one knows my fiancé and I are ttc our first together. I’m almost 26 and my family is basically waiting for me to pop a child out lol since I don’t have any. My fiancé has one child from a previous relationship. Well I’m 8 days late and Iv never been more the 3 days late which happened once like 2 months ago. I got off nexplanon in November and have been regular since. This is the first time Iv ever been this late. I had a bit of cramping on and off and there was a few times I thought af was coming but now I have no feeling of it coming and no cramping except very light ones here and there. I went to bed late last night (3:30am) and woke up at 5:30 am feeling awful. I just feel so off. I feel like I’m coming down with a cold my throat feels sore and scratchy but at the same time it doesn’t (sound weird but I can’t explain it) my nose is runny and I just feel so run down. My nipples are starting to feel sore which is odd because I get really sore breast the week before and during my period every cycle. That was the first sign I had something was off was when my breast weren’t sore when I expected af. TMI I have been gassy and about 2 weeks ago I went through a period of time I was constipated. I don’t have any reason as to why I’m this late. I have taken a couple test one was yesterday that were all BFN. I read a lot of people don’t get a positive until after 6 weeks some didn’t get any till week 9 my sister didnt test positive until she was 11 weeks.

Has anyone gone through this and tested negative but was pregnant and test positive further along since I would only be just over 5 weeks since my last period was June 21st. Or should. I start being concerned