I need help. Could I be pregnant?

For almost two weeks I haven't been feeling well. What had got me was that I've been very fatigue when usually I'm not. Then I started to get dizzy spells and I've been nauseous, I don't get sick I just tend to burp then get heart burn. I noticed that my stomach is bloated and it feels like its being stretched. I have both food aversions and cravings. But when I eat I feel full. I am not constipated. I noticed that I started to break out. My face and unfortunately my shoulders. I have been urinating constantly as well when I haven't drank anything. I have taken two hpt and both negative. I heard that some females pregnancy hormones aren't strong enough for the tests. My sense of smell has increased as well, when i was urniating one morning it smelt sweet. I know tmi. About two months ago I went for a vt sonogram and while she was looking she kept asking me if i was pregnant. I told her that I shouldn't be but I have been ually active with my boyfriend of many years. Well I just got a call back last week they want me to have another vt sonogram done monday because they said my endometrium lining was thick. When I asked my mom she said that that lining helps the egg catch onto...so I'm wondering if I was pregnant then and it was too early to detect.