11 days late HELP

Just did a pregnancy test and it was negative.

Been reading things online and it said sometimes pregnancy tests can show a negative when you’re carrying twins. My husband is a twin and he has a lot of twins in his family so I’ve started to think that might be a reason. We have been trying for 6 months and at this point I feel like I’m clutching on to any hope. My cycle is usually 33 days it’s been 45 days since my last period. Please help. I did my test after work so it wasn’t the first urine of the day..does that make a big difference. And is clear blue reliable?