Faint lines

I have taken about 15-18 tests since Thursday afternoon. Yes overboard I know. All of the lines are faint and are taking the full time allowed to show up. If they do not progress and get darker does that mean I'm more likely to have a miscarriage? My OB appontment is later this week and I'm driving myself crazy. Any advice please? -- If you do not have nice advice I ask that you please keep moving. Thanks and I hope everyone has a nice day. Happy Monday.