Not getting pregnant

When my husband and I were trying to get pregnant 2 years ago we got pregnant really fast within a month and a half. We’ve been trying for the past 5-6 months and have had 0 luck. Every test is negative. I know most people it takes years but I’m young and already have had 3 and all three were conceived pretty fast I must clarify that my first 2 were with someone else and he’s adopted them! We have 1 bio child together, I’ve been getting kinda bummed and wanna stop overthinking it but man does it hurt seeing those negatives 😔

Any advice my lovely lady’s ?