Friend not coming to wedding

Sooo, I’m getting married next month and just asked a group of my really close friends if they’ve sent their RSVP’s back yet (a group of 8). And one of my better said ‘not sure if I can make it any more if I don’t get a job soon’ whilst the others opened and didn’t reply which makes me think they’re not coming either. The thing is, they all just did an overseas contiki tour together a couple weeks ago for 2.5 weeks and they’ve had a whole year to save up and plan for it - all of them have had stable well paying jobs during the year at least! Plus I’ve been engaged for closer to 2 years so it’s not like they didn’t know it was coming. Am I just being paranoid or are they just being horrible friends? :(