So girls

So I've been having small little cramps like my period is going to start but it hasn't and it's about 3 weeks later but when I took a pregnancy test it came out negative I've been feeling alot of pressure and Been getting bigger my boyfriend even said the way I feel on my lower stomach doesn't feel the same as it did before I've also been gaining alot of weight recently just put ur prediction on here of what u think cause idk how it feels to be pregnant and sometimes I think the test are wrong