Pregnant!? What does it sound like to you?

Okay I know it is ALWAYS a possibility to be pregnant as long as someone is having sex. I am not denying that in the least. I am currently on Depo Provera, switching on the 14th to NuvaRing due to too many side effects from Depo. I was sick a few weeks back and was put on the antibiotic Azithromicin. I called my regular Doctor and both the nurse and Doctor said that it could interfere with Depo and to use a back-up for 30 days, I was reading a lot of information online and got confused not knowing which sites were reliable and which weren't. So I called my OB last Monday and had an appointment already for this past Thursday, I asked the nurse if there were drug interactions between the 2 and she said yes as well. So I left it at that. So when I went in for my appointment I had asked the nurse and she said since it is a derivative from penicillin that it would interact with the Depo, but to ask my Midwife just to be certain. She told me no it absolutely would not interfere with each other. I think she would have the best knowledge since she is the Midwife but with so many other people telling me otherwise I am nervous! I know it is possible to get pregnant on birth control period with out being on an antibiotic because that is how my son was conceived! My husband and I did have sex without using a back-up This past Saturday (9 Days ago.) For the past 5 days I have been nauseous, dizzy, and extremely tired ( to the point that after sleeping 10 hours a night I have to lay down and take a nap by noon, and I am still so exhausted by 9 pm I am ready for bed again! And sleep until 7-8 the next morning!) I know it is rare and near impossible to have pregnancy symptoms that early, I don't know if it is just my nerves or if I really am pregnant. Since I am on Depo and don't have a menses when do I take a pregnancy test? Do you think I am pregnant or do you think my nerves are getting the best of me? My sense of smell has also increased. I have NEVER been sensitive to smells, even when pregnant with my son but the slightest smell can make me so queasy I think I am gonna lose everything in my stomach! I haven't actually thrown up but I am pretty good about holding it back and I have been pretty close to it. Help me put my mind at ease, please! Any REAL answers are appreciated! Thanks!