Hi all, I'm so sorry for the long post but I'm at a loss and I don't know what else I can do or how much more I can take. I have had severe health anxiety for most of my adult life, I'm 27 years old and 22 weeks pregnant currently. I also take 50mg sertraline a day, as the doctor recommended I remain on my medication as the risks of me not having them outweigh any issues they may cause. Since taking this medication I've noticed a persistent pulse synchronised tinnitus in my right ear which after googling a lot could be down to the meds but now I'm unable to pacify myself with that and have convinced myself I have a brain tumour. Due to the fact I have been experiencing headaches, pressure/tension headaches which are located at the back of my head and worsen if I move around. This isn't everyday and I could go a week without having a headache but as soon as I do I'm back worrying I'm going to die. This could be caused by a number of things, pregnancy, the fact I have an infected molar on my right side, not drinking enough water, hormones etc - so why do I always go back to a tumour? I am absolutely crippled with fear but can't google symptoms to calm myself down in case I see something I don't want to. I haven't experienced any behaviour changes, speech issues or anything like that so I'm not sure why I can't shake this. I spoke to my doctor about this a lot over the last year and she has now referred me for an MRI to put my mind at rest and said that's the only reason as she doesn't see any red flags here. Please can someone give me some reassurance that this is my anxiety and I'm thinking irrationally? It's becoming harder and harder to get through the day now

Note: These headaches only started during pregnancy and can be relieved by pain medication.