Pregnant?

So I’m from Massachusetts but I’m vacationing in Dominican Republic. Long story short I’ve known this guy from DR for about 4 years but we have never had sex until now. (He’s clean don’t worry). Him and I have had unprotected sex on three different days now. On August 1st we had unprotected sex and he ejaculated inside of me. Then two days later he we had unprotected sex and he ejaculated inside me twice. And then I slept over his house last Sunday and we had unprotected sex again and he ejaculated inside of me three times which means he has ejaculated inside of me 6 times already.

Ever since Monday I’ve been feeling a little different. For example, I get very hungry, moody, I’m always nauseous and I’ve been experiencing some cramping. Besides that, I was also spotting this Sunday which isn’t normal because my period isn’t until August 29th. And my discharge has been very thick for two days now. I think there’s a chance that I could be pregnant so I told my sister about it and she says it’s all in my head. But I wasn’t convinced so I took a pregnancy test and it came out negative

Since it’s only been a week I’m thinking that there’s a chance that I am pregnant but it’s too soon for a pregnancy test to confirm it. So should I take another pregnancy test exactly on the 29th which is when I’m supposed to get my period? Do you guys think I could be pregnant?