As licensed health care providers, we are also going to give you some advice, or at least tell you what would be recommended in the situation you describe, because it is part of an oath that we take to attempt to help you and to prevent harm.
It is not normal to have palpitations after stopping marjiuana and chewing tobacco. It is possible to have an increased heart rate though, depending on how much you were using, and also depending on whether you might have an underlying anxiety disorder that you are not aware of. Anxiety causes the release of stress hormones which can cause palpitations, among other physical symptoms.
In more recent years it has been observed that there may
be a withdrawal syndrome from marijuana, somewhat similar to opiate
withdrawal (marijuana is very complex and contains many active chemicals - there has been found to be some with similarity to opiates - thus the pain relieveing qualities of marijuana) -- but the withdrawal would be much more spread out over time. There hasn't been research on this at this time. Due to growing techniques and technology, many of the strains of MJ today are much stronger than in the past. Because the active ingredients of (THC) is stored in fatty tissue, there is a gradual removal of the THC from the system over time, so although there may be some withdrawal, again it will be much mroe prolonged and less intense than of opiates and other substances. The withdrawal would not be physically dangerous, in other words.
Anxiety can be a side-effect of withdrawal elevate the heart rate or cause palpitations.
A documented common side effects of MJ withdrawal is increased REM or 'dream sleep'. This is because MJ suppresses REM sleep.
Additionally, many people that use MJ, nicotene and other addictive substances, do so because of underlying conditions, such as mood disorders and anxiety.
Because palpitations can sometimes be a sign of a dangerous arrythmia, and if the heart goes into certain arrythmias and individual can die, this is why we always advise anyone with an onset of arrythmias (palpitations) to be evaluated. Usually an EKG along with a physical exam can rule out any serious condition.
But without seeing an individual in person, it cannot be ruled out that there is a more dangerous underlying condition causing palpitations - thus we must recommend that a person with palpitations be evaluated.