People who down your news

So I'm excited that I'm pregnant it's my first time I've been trying for 10 months my hubby just went off for boot camp and according to the nature app I'm 4 weeks 1 day I'm 7 days late for my period and I'm never late and I've been nauseous the last few days and had 3 positive test and I have my first dr appointment next week my sister boyfriend keeps telling I shouldn't be excited because I don't know if I am actually pregnant and I could just think I am plus it's to early and I can loose it at any point and it's really starting to piss me off is it ok that I get mad at him for saying things like that or is he just telling me the truth? Btw here is my last 2 test top one taken at night at 4 days late and bottom with FMU at 5 days late