So nervous about chemical pregnancy...

Got a vfl on a First Response test yesterday at 11 DPO, another VFL this morning at 12 DPO. It got a tad bit darker. Is it weird that it’s such a faint line at 12 DPO? When I was pregnant in October, i had a very distinctive line at 12 DPO. ( I lost that pregnancy at 10 weeks) Just worried that its not going to progress. My period is due Tuesday.. 😐