Well, a whole lot of things can make you feel that way . . . everything from hormones to intermittent thyroid issues to anxiety and just to being overtired . . .
My suggestion would be that when you feel like this (not afterwards but during the episode), get blood work done . . . .I know it is expensive without insurance but sometimes something like thyroid dysfunction comes and goes (if you get tested for thyroid, ask for the full panel of TSH, Free T3, and Free T4 --- some docs will only do TSH which is the standard but my doc does T3 and T4 also because often that is where beginning dysfunction might appear . . .different docs do different things) . . . .
If you are experiencing stress and anxiety, then, yes, definitely this could be a symptom . . . when I am under stress / anxiety, even if I am sleeping, my mind is racing so I do not get restorative sleep . . . what I would suggest, other than professional intervention, is:
1. start a journal to see if you can discern a pattern of stress . . . sometimes little stresses are not recognizable but they all contribute to overall stress and anxiety;
2. look at your lifestyle . . . .especially sleep structure . . . when you go to sleep, get up, is it interrupted by television, telephones, ipods, texting, etc. . . . are you eating regularly and good stuff and doing some type of exercise . . .even walking . . . yeah, I know if you feel tired, why would you be walking but even if it is just 10 minutes, it might help to decrease hidden or overt anxiety / stress . . .
3. look for a free community-based self-help group . . . or a buddy . . . .sometimes when we share our issues, it helps and sometimes when we listen and help someone else, it helps us to understand what is going on in us
4. if at all possible, do seek a medical checkup or at least blood work and if all comes back fine, then ask for a referral to a counselor . . . it does no harm to check out how much they cost and sometimes if they know that you are on a fixed income, they will have a reduced rate . . . there are a couple where I live who do free counseling . . . now they only have one or two patients at a time, but at least they are trying . . . .they do require that they do a financial check because they really want to reach out to those who truly cannot afford help . . .
5. come back here . . .sometimes just chatting about it with others in a very safe and welcoming environment might help . . .take care, kc