I don't know of any effective treatment for concentration alone, Sharon. However, this is often a side-effect of depression or anxiety, so treating them will usually produce an improvement in concentration too.
Anxiety and depression tends to begin within a year or so of a significant life changing event such as bereavement, divorce, job loss, moving house, etc. Therefore, it isn't surprising that you might be struggling after being hit with 5 such events in 2 years.
Unfortunately, there are no quick and easy cures. The treatments take time, may make you feel worse initially and may worsen your concentration in the short term. However, it is also likely that without treatment you will progressively become worse and less able to cope. To complicate this even more, the longer these disorders are left to fester the harder it is to overcome them. So if at all possible I urge you to seek help now. The best person to guide you on the best treatment option for you is your physician.
In a nutshell, the only proven treatments for anxiety and depressive disorders are psychotherapy, specifically cognitive/behavioral therapy such as
or Rational Emotive Behavioral Therapy (
), or medication. These are usually very effective for about a third of patients and another third will improve to some degree.
If you have anxiety alone then that may be treated with a benzodiazepine such as alprazolam (Xanax), clonazepam (Klonopin) diazepam (Valium), and lorazepam (Ativan). These drugs have a number of advantages. They begin working within minutes, are usually effective and have minimum side-effects. As these are central nervous system depressants they are contraindicated for depression. The downsides are that they may make you drowsy for a few weeks, and because many doctors fear they cause dependency prescriptions can be hard to get and there are no guarantees that you will be able to obtain prescriptions in the future.
By dependency I don't mean addiction. They are not the same thing. You won't be strung out begging your friendly neighborhood drug dealer for a benzo fix. However, it will mean you shouldn't abruptly stop taking these drugs, but wean off them gradually over some weeks. That is the case for many drugs if taken for a length of time, including antibiotics, some heart medications, even vitamin C. OTOH, people can and do become so addicted to aspirin that they will
risk almost certain death
rather than quit taking it (no reason to stop using it occasionally but something to keep in mind).
For depression the best drugs are antidepressants, usually the SSRIs. Like CBT and REBT, they work well for about a 1/3 of patients, to some degree for another third, and do little for the remaining third. They can take 4-12 weeks to begin working and may make anxiety and depression worse in the initial weeks. Unlike the benzodiazepines which seem to work for most irrespective of which one you take, not all antidepressants work equally well for all patients. It typically takes 2 or 3 changes in medication and about 6 months to find the right antidepressant. While the dependency issue is focused on benzodiazepines, antidepressants will also cause dependency (so may psychotherapy, BTW, only therapists call it 'transference
While there are claims about the effectiveness for supplements such St Johns Wort, SAMe, kava and valerian, the data is weak . But there is growing evidence that exercise and omega-3/fish oil may be effective for moderate depression and anxiety. As both can boost brain activity, they may help with concentration too separately from any improvement due to an easing of anxiety or depression.