You know that gut feeling...

You know that gut feeling you get in the pit of your stomach when something happens. And you have that feeling you're right. Well thats what I just felt. Let me explain to you guys what happened! Okay so little backstory.. I'm married and in our relationship we've had a couple of bumpy roads. Mostly because of my brother in laws wife. I thought she was one of the nicest people I had met. But boy was I wrong!!! She always acted like I was another sister to her and she would always give me "good advice" which I thought back then that it was so "genuine". I was so blind and stupid. Well I came to find out my husband had dated her older sister. And I found that out like a year later. After I found that out everything clicked and made sense. Her sister was still into my husband so that why my BIL's wife was always trying to put things inside my head so I could leave my husband. After that her and her sister tried doing a lot of horrible things to me. And they would message me and tell me shit that her and my husband had done. By that time we had cut my BIL's wife out of our lives. But we would still see her at my MIL's house. So fast forward me and my husband changed our numbers. And after a year my BIL's wife still tries to tell me shit when we bump into each other which is really stupid and immature. Mind you that I'm 22 and she's like 26 with two kids.
So now that you guys know what a witch she is I can tell you guys what happened a while ago. My husband received a confirmation code from Facebook (neither of us has a fb). Which was freaking weird and I flipped out and asked him if he had made one and he said no. And mind you he had to be on fb that exact minute to receive that confirmation. So we started thinking who could've done that. And then all of a sudden I get a request on Instagram of a fake profile that has my husbands last name. Ironic isn't it🙄
Well I had a gut feeling it has to be them because only family has my husbands number. And she could of easily gotten it from my BIL phone. I just have a gut feeling it's her. And she has tried to add me on my Instagram before but I just ignore it. I'm just so tired of these stupid games. A married women with kids and doing all this shit. Like why can't I just live and be happy with my husband without people trying to get in between us! I don't even know if I should try and confront her or not do anything. Sorry for the long rant. Any advice you guys can give me? Or what I can do in this situation😭. I need to have proof in order to accuse her of anything.