Pregnant after vasectomy?

My husband had a vasectomy in May last year. He never went back to check and see if it worked. We’ve been really, really careful anyway just because you never know. Well, that last time we had sex was the day I ovulated and he did not pull out. It felt like one of those times when we were trying to get pregnant. I thought, crap! right after it happened, but also that we were probably safe because he got snipped. Well, I forgot about it until 3 days ago where I’ve just felt SO pregnant. My boobs hurt. I’m crampy. My boobs started leaking milk again and I haven’t nursed in 10 months. I’m exhausted and hungry and cranky. I just don’t feel like myself. I took a test this morning and it was negative. The test has been sitting in my drawer since 2016 so I’m not sure if it’s old. But I’m also pretty early, I’m not due for a period for a week. Could I be pregnant? I think I would be more surprised if I weren’t because of how crazy I feel. I’m so confused!