Yes your concern is normal but till now many people have taken those vaccine available specially Oxford astrageneca,sinovac and pfizer.But there was no evidence of blood clot or thrombosis or other situations you mentioned.But some people experienced fever,runny nose,nausea,weakness and some minor side effects but very much negligible.
We all know that covid itself a hyercoagulable state.It increase d dimer in the blood means there is higher risk of formation and dislodgement of clot and that may produce lethal situation with Pulmonary embolism,cardiac arrest or stroke.So if some person are at that state and take vaccine it will not be effective to prevent the situation and its not the fault of the vaccine.Vaccine are designed to reduce the fatality if it introduced early.
We all know that its pretty much difficult to design a cent percent effective vaccine Against it Because of its rapid changing of strain but its recommended to take those available vaccine to reduce the fatality and to create a shield against certain fatal strains.
In future i will try to make a vlog regarding it.Thank you.♥️