Pregnant or stressed?

Julie

So I’m now 15 days late going on 16 days tomorrow late of my period. I haven’t been able to make it anywhere to buy a test because I have to replace a flat tire on my car and my boyfriend works all day. I’m a stay at home mom. However, my boyfriend had a vasectomy done a while ago and I’ve heard stories of people getting pregnant even when their partner had a vasectomy done. He thinks I’ve been stressing myself out too much lately but I’ve felt fine. Last night a while after I laid down to go to bed I started to feel bad and then ended up getting sick and I’ve felt bad all day. He also says I’ve been getting bent out of shape lately and that I’ve been different and he doesn’t know how to explain it. So I don’t know if I might be pregnant or if I’m just stressed and have really delayed my period. Someone help me please.