Now I'm 5 days late and neg hpt

I'm getting so frustrated with ttc. My husband and I have been trying for 5 months and I'm now 5 days late and my period nor are there any signs it's coming  but a negative hpt just bums me out. Could I be too early to detect pregnancy hormone? Should I take another in a a few days when my period is 7-10 days late? Oh I need some baby dust sprinkled on me ASAP.  This is baby #3 so we know even though I'm overweight I can conceive. Need some advice girls!           ????