Stressing

So I’ve been trying to get pregnant for some time now I just turned 30 in March, two kid an 11 yo daughter and a 10yo boy. I believe things happen for a reason, I’m 3 days late and I’m stressing do I just go with the flow, or do I go get a test. I’ve seriously been trying for at least 3-3 1/2 maybe 4 years.... and man I’ve gone through a lot, can I handle it, can I really do this all over again??? Idk someone talk to me😫