Light positive hcg test; then negative, w/irregular period with a random spontaneous bleed; but husband has vasectomy.this has happened twice,plz help?

I recommend: have your husband tested with a semen analysis (sperm count.) Even if this was done after his vasectomy before, check him again. Two false positives on hPT would not be impossible, but be highly unlikely. If - and I mean this 100% politely, but needs to be said - you are sexually active with any other men, the issue may lie there. Good wishes.