What could be going on ?

I was told that I wouldn’t be able to get pregnant or it would take a lot of tries so I don’t know why I’m so worried but I really hope that I can have a baby.

I’m currently 18 days late and I took a pregnancy test and it came out negative... I’ve been feeling sick for a couple days now ... should I take another test ?

I was really sad that It came out negative because I was feeling symptoms and was excited to start a family .. and I feel awful because I feel like I have been failing my boyfriend with not being able to give him a baby.