If you have been using marijuana frequently, it can cause a lot of problems like anxiety, restlessness, fearfulness, etc. The most important thing is to stop it, along with stopping alcohol and any other drugs you may be taking.
Consult a psychiatrist with experience in deaddiction, who will be able to help you.
If you begin to feel suicidal or hopeless, consult a psychiatrist immediately. Usage of any drugs of abuse/ recreational drugs can cause or trigger mental illness. Marijuana also acts a gateway drug, meaning its use can make you more susceptible to try other drugs.