I don't normally have this problem...but when it happens, it's usually been due to stress, often big projects and so forth.
I find Shivani made a lot of good suggestions, a few of which I do regularly and it probably helps keep my sleep regular:
1) avoid computers or phones for work at night...if you use them, use them to read and engage with something that keeps your mind focused and not overly agitated. Queue up key items or issues for later meditation or discussion with your guides, etc.
2) have a cup of herbal tea as a nightly ritual. Very calming. You can do a valerian tea blend if you find regular herbal teas are not helping enough.
3) yoga nidra - cannot say enough about this mediation. I feel it's one of the best parts of the day and I usually cannot wait. Sometimes you will fall asleep quickly and other times not, but in any case, your mind will be focused and calm. Many times I wanted to review something but fell asleep midstream...sigh. So then you just push it to the next evening's meditation...LOL.
4) hiking in the woods at least a few times a week...a mental health necessity IMO if you can get to some green outdoors nearby. This is walking meditation and I absolutely recommend you take your issues there and discuss what is coming to the surface. It's great to take a partner to hike and talk and vent...but can be done solo as well.
Hopefully some of these will help...best of luck!
Peace & blessings
Bound by conventions, people tend to reach for what is easy.
Here we must be unafraid of what is difficult.
For all living beings in nature must unfold in their particular way
and become themselves despite all opposition.
-- Rainer Maria Rilke