Bipolar depression or something physical?

For the past few weeks, I (22F) have been struggling with low energy. It started gradually, as I was able to exercise frequently but was sleeping in later and later. Now I am at the point where I am lucky if I wake up before noon and get out of bed before 1pm. It doesn't matter how much or how little I sleep. I will feel the same whether it's four hours or twelve hours. It's been really hard to continue exercising, so I have reduced the frequency and intensity of my work outs.

I've been incredibly bloated, my muscles feel sore and stiff, especially my neck. Today it has started randomly twitching every so often, and there is a tightness in my throat. I feel like I can't focus on anything, and nothing I am saying or writing is as coherent as I would like it to be. Although, that could be my own insecurity talking.

I felt incredibly dizzy yesterday, and almost passed out getting up to get water. My hearing went out for a few seconds when it happened. I am sort of stumbling around as well, even when not dizzy. I just feel like I've lost my balance. I haven't fallen yet, but I have definitely had to catch myself a few times. I feel really sad, irritable, and out of it.

I have spent a lot of time outside in the heat, but I have tried to be mindful of rehydrating. I eat enough and I eat nutritiously. I am 140lbs and 5'7. I also am bloated most of the time, and it seems to have gotten worse recently.

I have a history of iron deficiency. My ferritin level was 6 in October, but it increased to the 50s by December, and I take Ferrous Sulfate every other day with vitamin C. I am also diagnosed with bipolar 2 disorder, and do get frequent depressive episodes, so I am wondering if I could be experiencing one without realizing. I take Lamotrigine 100mg two times a day.

I am just so tired of feeling this way. I want my energy back. If anyone has ideas on what it could be, please let me know.