Very frustrating!

So, my LMP was 7/7 and I haven't had any signs of starting but I spotted very lightly a few times last month. I've spent a fortune on HPTs just to get negatives every time. Someone said they think I'm pregnant with twins and that it would make my HCG levels too high for a urine test. Should I pay out of pocket for a blood test and US (I don't have insurance) or should I stop obsessing over it and wait for my period to show up again?