Are HCG levels lower in older women?

I'm 41 and 2 days late and usually pretty regular. I took a FRER this morning and it was negative. I was pregnant in my 20s and got a strong positive test one day before period was supposed to start. I don't really have any of (MY) personal normal AF symptoms. I am having some low abdomen pain and the top of my abdomen feels like I've been doing crunches. The only af symptoms I ever get are really creamy CM and I get very sad and depressed and sometimes spot ting and haven't had either of those. . So wondering if I'm out or if I should test again ?