Sounds like your insulin is not working properly. This is a "fast-acting" insulin and should be kicking in right after you meal. Check the product insert data sheet included with the insulin for specifics. Talk with your medical professional ASAP and/or get another fresh vial of insulin.
I take Novolog and it begins to work within several minutes after injection. The product insert warns me to make certain to eat within 5 to 10 minutes after injection. It peaks within 3 hours of injection.
Good luck and check your problem out ASAP.