Maybe I'm crazy?

So I've been really emotional and just "in my head" for the past almost two weeks... I get like this sometimes and all it successfully does is make my marriage harder and makes me paranoid and whatnot.. I've been having the strangest, close to scaring nightmares about family members that I don't even want to mention bc it makes me cringe and feel sick which has been bothering me so bad. Another thing is my husband being so buddy buddy with his older brothers wife, they've been friends for years and I never thought twice about it until just the other day I mentioned something about her I don't even remember what it was but he got defensive about it and I brought up that he always takes "the other persons side" which is true tbh no matter who it is.. Of course he denied it and it made me think of how paranoid I am about him not being faithful bc he's been acting weird.. Which feels just like my mind jacking with me. My period is also over a week late which isn't extremely uncommon but it freaks me out a little. Idk I felt the need to vent for whatever reason I'm feeling so insecure and crazy..