Vvvvvfaint positive??

I'm 10dpo and I took a hpt with fmu and I got a very faint line and my husband could see it too but after about 30 minutes the line disappeared. It was so weird. Has anyone else had this happen to them?? It's our first month ttc so I'm not getting my hopes up to high buy it's kind of a bummer to see a positive and then it disappear. I'm testing again tomorrow morning but has anyone had any similar stories?