You do need to see a doctor. It sounds like it might be thyroid, but who can tell? You need a good checkup. If you can't afford a doctor, research what resources are available at community health clinics.
Anxiety and depression (even at low levels) can cause a host of physical symptoms. However, there are some physical conditions that can mimic the symptoms you describe. Even if you do not have insurance, it is important that you get a check up from a doctor. You can go to your local clinic (most counties have them) for relatively low cost. The dr. will determine what, if any, tests should be done. Either way, you can receive treatment for what's going on.
I would trust the doctor more than my comment, but from your description of your ailments " My neck is very stiff as well" was sort of a clencher- I would go to the doctor and have your throat checked (thyroid) for a goiter or inflammation, It could also be due to external sources, or in my case a combination of the two. Thyroid issues can still arise even though you are still happy with life. You said you were on birth control so I assume you are female, Hypothyroidism is more common in females than males (although I have it and I am a male). Head to the doctor! stress or otherwise, it is something that should be brought up.
The way you describe your life and your symptoms suggest two alternative causes..one starting in your body, like thyroid or some inflammatory process; the other being stress, which can cause the same symptom picture. You should get a medical check up, and also start thinking about a conflict you are having with yourself, rather than the world where everything is going well.
It sounds as though you are feeling your life is out of control despite feeling happy.
Your symptoms could be due to many things: stress, anxiety, pregnancy, ...
Could the source of your anxiety from two years ago be present now?
Some light, gentle activity could possibly help your anxiety.
The symptoms do appear related. Feeling issues doesn't mean the problem, the issue or the anxiety, isn't in or created in your head. Many body complaints are caused through stress and anxiety.
I'm thinking pregnancy despite the birth control. I could be very, very wrong.
J