Are Gaviscon And Omeprazole The Right Medication For Gastritis?

Hi. I am an 18 year old woman. I was in the hospital today and diagnosed with gastritis. Ive had tummy aches for a month now and they have gotten very bad in the past week. I was given Omeprazole by a walkin clinic doctor a few days ago because they thought i had an ulcer, i was told to take this medication and hopefully itd get better in a few weeks. I ended up going to the hospital because the pain was awful and they gave me a medicine to coat my stomach. I was supposed to buy Maalox over the counter but the pharmacist said they only had Gaviscon original. I bought this and I am wondering if it will be good enough of a combo with the omeprazole to help my stomach get better. I am having a lot of trouble sleeping and sitting in general and was wondering if I would be able to vape marijuana as well to help with the stomach aches and nausea.