Where did my symptoms go?

I'm 5 weeks today and for first half of week 4 I had tons of symptoms... frequent urination, breast tenderness, slight (implantation) cramping, fatigue and feeling bloated. My symptoms have almost disappeared for 4 days now... has this happened to anyone else? I'm can't stop worrying that I have or will miscarry. Has this happened to anyone else for more than few days? Help! p.s this is our 3rd round of FET.