Ok everyone, I need a little help. Who has experienced implantation bleeding and knows what it looks like?

My period was supposed to start on Monday, it's now Thursday. My period is usually like clockwork, maybe a day or too off. Well come Monday and no period. About midday I notice a little spotting in my underwear when I went to the bathroom. I thought alright my period started so I put in a tampon and went about my day. Few hours later I went to the bathroom, took out my tampon and it barely had anything on it. It was like a light tanish color. Not red at all. Not a speck of red.

Usually I experience a little pelvic pain right before my period too and I did on maybe Saturday. I can't remember.

I've been my usual moody self leading up to my supposed period date, sore boobs and all. But still no period.

I wonder if the spotting I had was implantation bleeding or something else? Anyone have thoughts on this? I'm still confused.

Thanks!

Update-

So I've been have indigestion like crazy the last few days. Also my boobs were super sore last week but now just my nipples are super duper sensitive. I'm going to wait a few more days before I test.