Is this true?

So I read that sometimes your HCG levels are too high to show up on a test and sometimes you need to dilute your pee with water. I'm pretty much obsessed right now, because my period didn't come, I've been irregular since getting off depo. I have 2 kids, but we're trying for #3, and I feel all out of sorts. I'm losing weight, but my pants fit tighter, smells make me feel carsick, and while I haven't actually vomited, I feel exremely nauseous after eating. I also read that pregnancy symptoms could be a sign of hormone withdrawal from stopping depo, but I've been off depo for over a year.